View source for Cardiology

{{short description|Branch of medicine dealing with the heart}}
{{about|the medical speciality|the album|Cardiology (album)|the medical journal|Cardiology (journal)}}
{{Infobox medical speciality
| title        = Cardiology
| subdivisions = {{bulleted list |Interventional Cardiology, |Clinical Cardiac Electrophysiology, |Heart Failure and Transplant Cardiology, |Nuclear Cardiology, |Adult Congenital Heart Disease, |Pediatric Cardiology, |Echocardiography, |Cardiovascular Imaging}}
| image        = [[File:Heart diagram blood flow en.svg|225px]]
| caption      = Blood flow diagram of the human heart. Blue components indicate de-oxygenated blood pathways and red components indicate oxygenated blood pathways.
| system       = [[Cardiovascular system|Cardiovascular]]
| diseases     = {{bulleted list |[[Cardiovascular disease|Heart (or cardiovascular) disease]] and [[heart failure]],  |[[atherosclerosis]] and [[coronary artery disease]], |[[atrial fibrillation]] and other [[arrhythmia]]s, |[[cardiomyopathy]], |[[Hypertension|hypertension (high blood pressure)]], |[[congenital heart disease]]}}
| tests        = [[Cardiology diagnostic tests and procedures|Blood tests, electrophysiology study]], [[cardiac imaging]], [[ECG]], [[echocardiogram]]s, [[Cardiac stress test|stress test]]
| specialist   = Cardiologist
| glossary   = [[Glossary of medicine]]
}}
{{Infobox Occupation
| name= Cardiologist
| image=
| caption=
| official_names=
* Physician
* Surgeon
| type= [[Specialty (medicine)|Specialty]]
| activity_sector= [[Medicine]], [[Surgery]]
| competencies=
| formation=
* [[Doctor of Medicine]] (M.D.)
* [[Doctor of Osteopathic Medicine]] (D.O.)
* [[Bachelor of Medicine, Bachelor of Surgery]] (M.B.B.S.)
* [[Bachelor of Medicine, Bachelor of Surgery]] (MBChB)
| employment_field= [[Hospital]]s, [[Clinic]]s
| related_occupation=
}}

'''Cardiology''' ({{ety|grc|''καρδίᾱ'' (kardiā)|heart||-''λογία'' ([[wikt:-logia|-logia]])|study}}) is the study of the heart. Cardiology is a branch of [[medicine]] that deals with disorders of the [[heart]] and the [[cardiovascular system]]. The field includes [[medical diagnosis]] and treatment of [[congenital heart defect]]s, [[coronary artery disease]], [[heart failure]], [[valvular heart disease]], and [[electrophysiology]]. [[Physician]]s who specialize in this field of medicine are called '''cardiologists''', a sub-specialty of [[internal medicine]]. Pediatric cardiologists are [[pediatrician]]s who specialize in cardiology. Physicians who specialize in cardiac surgery are called '''[[cardiothoracic surgeon]]s''' or '''cardiac surgeons''', a specialty of [[general surgery]].<ref>{{Cite web |last=Herper |first=Matthew |date=December 5, 2017 |title=27 Top Cardiologists, Picked By Big Data |url=https://www.forbes.com/sites/matthewherper/2017/12/05/27-top-cardiologists-picked-by-big-data/ |access-date=June 2, 2022 |website=Forbes |language=en-US}}</ref>

== Specializations ==
All cardiologists in the branch of medicine study the disorders of the heart, but the study of adult and child heart disorders each require different training pathways. Therefore, an adult cardiologist (often simply called "cardiologist") is inadequately trained to take care of children, and pediatric cardiologists are not trained to treat adult heart disease. Surgical aspects outside of cardiac rhythm device implant are not included in cardiology and are in the domain of [[cardiothoracic surgery]]. For example, [[coronary artery bypass surgery]] (CABG), [[cardiopulmonary bypass]] and [[valve replacement]] are surgical procedures performed by surgeons, not cardiologists. Typically a cardiologist would first identify who is in need of cardiac surgery and refer them to a cardiac surgeon for the procedure. However, some invasive procedures such as [[cardiac catheterization]] and [[Artificial cardiac pacemaker#Insertion|pacemaker implantation]] are performed by cardiologists.

===Adult cardiology===
Cardiology is a specialty of [[internal medicine]].

To become a cardiologist in the [[United States]], a three-year residency in internal medicine is followed by a three-year fellowship in cardiology. It is possible to specialize further in a sub-specialty. Recognized sub-specialties in the U.S. by the [[Accreditation Council for Graduate Medical Education]] are [[clinical cardiac electrophysiology]], [[interventional cardiology]], adult congenital heart disease, and advanced heart failure and transplant cardiology. Cardiologists may further become certified in echocardiography by the National Board of Echocardiography,<ref>echoboards.org</ref> in nuclear cardiology by the Certification Board of Nuclear Cardiology, in cardiovascular computed tomography by the Certification Board of Cardiovascular Computed Tomography in cardiovascular MRI by the Certification Board of Cardiovascular Magnetic Resonance.<ref>apca.org/certifications-examinations/cbnc-and-cbcct/</ref> Recognized subspecialties in the U.S. by the [[American Osteopathic Association Bureau of Osteopathic Specialists]] include [[clinical cardiac electrophysiology]] and [[interventional cardiology]].<ref>{{cite web|title=Specialties & Subspecialties|url=http://www.osteopathic.org/inside-aoa/development/aoa-board-certification/Pages/specialty-subspecialty-certification.aspx|publisher=American Osteopathic Association|access-date=23 September 2012|archive-url=https://web.archive.org/web/20150813083503/http://www.osteopathic.org/inside-aoa/development/aoa-board-certification/Pages/specialty-subspecialty-certification.aspx|archive-date=2015-08-13|url-status=dead}}</ref>

In India, a three-year residency in General Medicine or Pediatrics after [[M.B.B.S.]] and then three years of residency in cardiology are needed to be a D.M. (holder of a Doctorate of Medicine [D.M.])/[[Diplomate of National Board]] (DNB) in Cardiology.{{citation needed|date=April 2021}}

Per [[Doximity]], adult cardiologists earn an average of $436,849 per year in the U.S.<ref name=r1>Hamblin, James (January 27, 2015) [https://www.theatlantic.com/health/archive/2015/01/physician-salaries/384846/ What Doctors Make]. theatlantic.com</ref>

==== Cardiac electrophysiology ====
{{Main|Cardiac electrophysiology}}

Cardiac electrophysiology is the science of elucidating, diagnosing, and treating the electrical activities of the heart. The term is usually used to describe studies of such phenomena by invasive (intracardiac) [[Cardiac catheterization|catheter]] recording of spontaneous activity as well as of cardiac responses to [[programmed electrical stimulation]] (PES). These studies are performed to assess complex [[arrhythmia]]s, elucidate symptoms, evaluate abnormal [[electrocardiograms]], assess risk of developing arrhythmias in the future, and design treatment.  These procedures increasingly include therapeutic methods (typically [[radiofrequency ablation]], or [[cryoablation]]) in addition to diagnostic and prognostic procedures.

Other therapeutic modalities employed in this field include [[antiarrhythmic drug]] therapy and implantation of [[artificial pacemaker|pacemakers]] and automatic [[implantable cardioverter-defibrillators]] (AICD).<ref name=Fauci>Fauci, Anthony, et al. ''Harrison's Textbook of Medicine''. New York: McGraw Hill, 2009.</ref><ref>Braunwald, Eugene, ed. ''Heart Disease, 6th edition.'' Philadelphia: Saunders, 2011.</ref>

The cardiac [[electrophysiology study]] typically measures the response of the injured or cardiomyopathic myocardium to PES on specific pharmacological regimens in order to assess the likelihood that the regimen will successfully prevent potentially fatal sustained [[ventricular tachycardia]] (VT) or [[ventricular fibrillation]] (VF) in the future. Sometimes a ''series'' of electrophysiology-study drug trials must be conducted to enable the cardiologist to select the one regimen for long-term treatment that best prevents or slows the development of VT or VF following PES. Such studies may also be conducted in the presence of a newly implanted or newly replaced cardiac pacemaker or AICD.<ref name=Fauci />

==== Clinical cardiac electrophysiology ====
{{Main|Clinical cardiac electrophysiology}}

Clinical cardiac electrophysiology is a branch of the medical specialty of cardiology and is concerned with the study and treatment of rhythm disorders of the heart. Cardiologists with expertise in this area are usually referred to as electrophysiologists. Electrophysiologists are trained in the mechanism, function, and performance of the electrical activities of the heart. Electrophysiologists work closely with other cardiologists and cardiac surgeons to assist or guide therapy for heart rhythm disturbances (arrhythmias). They are trained to perform interventional and surgical procedures to treat cardiac arrhythmia.<ref name="pmid35695795">{{cite journal | vauthors = Cox JL, Churyla A, Malaisrie SC, Kruse J, Kislitsina ON, McCarthy PM | title = A history of collaboration between electrophysiologists and arrhythmia surgeons | journal = J Cardiovasc Electrophysiol | volume = 33 | issue = 8 | pages = 1966–1977 | date = August 2022 | pmid = 35695795 | pmc = 9543838 | doi = 10.1111/jce.15598 }}</ref>

The training required to become an electrophysiologist is long and requires eight years after medical school (within the U.S.). Three years of internal medicine residency, three years of cardiology fellowship, and two years of clinical cardiac electrophysiology.<ref name="pmid30566044">{{cite journal | vauthors = DeMazumder D | title = The Path of an Early Career Physician and Scientist in Cardiac Electrophysiology | journal = Circ Res | volume = 123 | issue = 12 | pages = 1269–1271 | date = December 2018 | pmid = 30566044 | pmc = 6338224 | doi = 10.1161/CIRCRESAHA.118.314016 }}</ref>

==== Cardiogeriatrics ====
{{Main|Cardiogeriatrics}}

Cardiogeriatrics, or geriatric cardiology, is the branch of cardiology and geriatric medicine that deals with the cardiovascular disorders in elderly people.

Cardiac disorders such as [[coronary heart disease]], including [[myocardial infarction]], [[heart failure]], [[cardiomyopathy]], and arrhythmias such as [[atrial fibrillation]], are common and are a major cause of mortality in elderly people.<ref>{{Cite web|url=https://www.cdc.gov/nchs/data/ahcd/agingtrends/06olderpersons.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.cdc.gov/nchs/data/ahcd/agingtrends/06olderpersons.pdf |archive-date=2022-10-09 |url-status=live|title=Trends in Causes of Death among Older Persons in the United States}}</ref><ref>{{cite journal | vauthors = Dodson JA | title = Geriatric Cardiology: An Emerging Discipline | journal = Canadian Journal of Cardiology | date=September 2016 | doi = 10.1016/j.cjca.2016.03.019 |volume=32|issue=9| pages = 1056–1064 | pmid = 27476988| pmc = 5581937 }}</ref> Vascular disorders such as [[atherosclerosis]] and [[peripheral arterial disease]] cause significant morbidity and mortality in aged people.<ref>{{Cite journal|last1=Golomb Beatrice A.|last2=Dang Tram T.|last3=Criqui Michael H.|date=2006-08-15|title=Peripheral Arterial Disease|journal=Circulation|volume=114|issue=7|pages=688–699|doi=10.1161/CIRCULATIONAHA.105.593442|pmid=16908785|s2cid=5364055|doi-access=free}}</ref><ref>{{Cite journal|last1=Yazdanyar|first1=Ali|last2=Newman|first2=Anne B.|date=2010-11-01|title=The Burden of Cardiovascular Disease in the Elderly: Morbidity, Mortality, and Costs|journal=Clinics in Geriatric Medicine|volume=25|issue=4|pages=563–vii|doi=10.1016/j.cger.2009.07.007|issn=0749-0690|pmc=2797320|pmid=19944261}}</ref>

==== Imaging ====
{{further|Echocardiography|Cardiac magnetic resonance imaging|Computed tomography of the heart}}

Cardiac imaging includes echocardiography (echo), cardiac magnetic resonance imaging (CMR), and computed tomography of the heart.
Those who specialize in cardiac imaging may undergo more training in all imaging modes or focus on a single imaging modality.

Echocardiography (or "echo") uses standard two-dimensional, three-dimensional, and [[Doppler ultrasound]] to create images of the heart. It is used to evaluate and quantify cardiac size and function, valvular function, and can assist with diagnosis and treatment of conditions including heart failure, heart attack, valvular heart disease, congenital heart defects, pericardial disease, and aortic disease. 
Those who specialize in echo may spend a significant amount of their clinical time reading echos and performing transesophageal echo, in particular using the latter during procedures such as insertion of a left atrial appendage occlusion device. Transesophageal echo provides higher spatial resolution than trans thoracic echocardiography and because the probe is located in the esophagus, it is not limited by attenuation due to anterior chest structures such as the ribs, chest wall, breasts, lungs that can hinder the quality of trans thoracic echocardiography. It is generally indicated for a variety of indications including: when the standard transthoracic echocardiogram is non diagnostic, for detailed evaluation of abnormalities that are typically in the far field, such as the aorta, left atrial appendage, evaluation of native or prosthetic heart valves, evaluation of cardiac masses, evaluation of endocarditis, valvular abscesses, or for the evaluation of cardiac source of embolus. It is frequently used in the setting of atrial fibrillation or atrial flutter to facilitate the clinical decision with regard to anticoagulation, cardioversion and/or radio frequency ablation.<ref>aseecho.org</ref>

Cardiac MRI utilizes special protocols to image heart structure and function with specific sequences for certain diseases such as [[hemochromatosis]] and [[amyloidosis]].

Cardiac CT utilizes special protocols to image heart structure and function with particular emphasis on coronary arteries.

==== Interventional cardiology ====
{{Main|Interventional cardiology}}

Interventional cardiology is a branch of cardiology that deals specifically with the [[catheter]] based treatment of structural heart diseases.<ref>{{Cite journal |last=King |first=Spencer B |date=March 1998 |title=The Development of Interventional Cardiology |url=https://doi.org/10.1016/S0735-1097(97)00558-5 |journal=Journal of the American College of Cardiology |volume=31 |issue=4 |pages=64B–88B |doi=10.1016/s0735-1097(97)00558-5 |pmid=9530288 |issn=0735-1097|url-access=subscription }}</ref> A large number of procedures can be performed on the heart by catheterization, including angiogram, angioplasty, atherectomy, and stent implantation. These procedures all involve insertion of a sheath into the [[femoral artery]] or radial artery (but, in practice, any large peripheral artery or vein) and [[cannula]]ting the heart under {{Nowrap|X-ray}} visualization (most commonly [[fluoroscopy]]). This cannulation allows indirect access to the heart, bypassing the trauma caused by surgical opening of the chest.

The main advantages of using the interventional cardiology or radiology approach are the avoidance of the scars and pain, and long post-operative recovery. Additionally, interventional cardiology procedure of primary [[angioplasty]] is now the gold standard of care for an acute myocardial infarction. This procedure can also be done proactively, when areas of the vascular system become occluded from [[atherosclerosis]]. The Cardiologist will thread this sheath through the vascular system to access the heart. This sheath has a balloon and a tiny wire mesh tube wrapped around it, and if the cardiologist finds a blockage or [[stenosis]], they can inflate the balloon at the occlusion site in the vascular system to flatten or compress the plaque against the vascular wall. Once that is complete a [[stent]] is placed as a type of scaffold to hold the vasculature open permanently.

====Cardiomyopathy/heart failure====
A relatively newer specialization of cardiology is in the field of heart failure and heart transplant. Cardiomyopathy is a disease of the heart muscle that make it larger or stiffer, sometimes making the heart worse at pumping blood.<ref>{{Cite web |title=Cardiomyopathy |url=https://medlineplus.gov/cardiomyopathy.html |access-date=2024-06-03 |website=medlineplus.gov}}</ref> Specialization of general cardiology to just that of the [[cardiomyopathy|cardiomyopathies]] leads to also specializing in [[heart transplant]] and [[pulmonary hypertension]].

====Cardiooncology====
{{main|Cardiooncology}}
A recent specialization of cardiology is that of cardiooncology.
This area specializes in the cardiac management in those with cancer and in particular those with plans for [[chemotherapy]] or those who have experienced cardiac complications of chemotherapy.

=== Preventive cardiology and cardiac rehabilitation ===
{{further|Cardiac rehabilitation}}
In recent times, the focus is gradually shifting to preventive cardiology due to increased [[cardiovascular disease]] burden at an early age. According to the WHO, 37% of all premature deaths are due to cardiovascular diseases and out of this, 82% are in low and middle income countries.<ref>{{Cite web|url=https://www.who.int/news-room/fact-sheets/detail/cardiovascular-diseases-(cvds)|title=Cardiovascular diseases (CVDs)|website=www.who.int|language=en|access-date=2019-05-14}}</ref> Clinical cardiology is the sub specialty of cardiology which looks after preventive cardiology and cardiac rehabilitation. Preventive cardiology also deals with routine preventive checkup though noninvasive tests, specifically electrocardiography, [[fasegraphy]], stress tests, [[lipid profile]] and general physical examination to detect any cardiovascular diseases at an early age, while cardiac rehabilitation is the upcoming branch of cardiology which helps a person regain their overall strength and live a normal life after a cardiovascular event. A subspecialty of preventive cardiology is [[sports cardiology]]. Because heart disease is the leading cause of death in the world including United States (cdc.gov), national health campaigns and randomized control research has developed to improve heart health.

===Pediatric cardiology===
[[File:Heart tetralogy fallot.svg|thumb|Tetralogy of Fallot]]
[[Helen B. Taussig]] is known as the founder of pediatric cardiology. She became famous through her work with [[Tetralogy of Fallot|Tetralogy]] congenital heart defect in which [[Oxygenated blood|oxygenated and deoxygenated blood]] enters the circulatory system resulting from a [[ventricular septal defect]] (VSD) right beneath the aorta. This condition causes newborns to have a bluish-tint, [[cyanosis]], and have a deficiency of oxygen to their tissues, [[hypoxemia]]. She worked with [[Alfred Blalock]] and [[Vivien Thomas]] at the [[Johns Hopkins Hospital]] where they experimented with dogs to look at how they would attempt to surgically cure these "blue babies". They eventually figured out how to do just that by the [[anastomosis]] of the systemic artery to the pulmonary artery and called this the [[Blalock–Taussig shunt|Blalock-Taussig Shunt]].<ref>{{Cite journal|last=Murphy|first=Anne M.|date=2008-07-16|title=The Blalock-Taussig-Thomas Collaboration|journal=JAMA|volume=300|issue=3|doi=10.1001/jama.300.3.328|issn=0098-7484|pages=328–30|pmid=18632547|doi-access=free}}</ref>

[[Tetralogy of Fallot]], [[pulmonary atresia]], [[double outlet right ventricle]], [[Transposition of the Great Arteries|transposition of the great arteries]], [[persistent truncus arteriosus]], and [[Ebstein's anomaly]] are various congenital cyanotic heart diseases, in which the [[blood]] of the newborn is not oxygenated efficiently, due to the heart defect.

===Adult congenital heart disease===
As more children with congenital heart disease are surviving into adulthood, a hybrid of adult and pediatric cardiology has emerged called adult congenital heart disease (ACHD).
This field can be entered as either adult or pediatric cardiology.
ACHD specializes in congenital diseases in the setting of adult diseases (e.g., coronary artery disease, COPD, diabetes) that is, otherwise, atypical for adult or pediatric cardiology.

== The heart ==
[[File:Latidos.gif|thumb|Blood flow through the valves]]

{{main|Heart}}

As the center focus of cardiology, the heart has numerous anatomical features (e.g., [[atrium (heart)|atria]], [[Ventricle (heart)|ventricle]]s, [[heart valve]]s) and numerous physiological features (e.g., [[systole (medicine)|systole]], [[heart sounds]], [[afterload]]) that have been encyclopedically documented for many centuries. The heart is located in the middle of the abdomen with its tip slightly towards the left side of the abdomen.

Disorders of the heart lead to [[heart disease]] and cardiovascular disease and can lead to a significant number of deaths: cardiovascular disease is the leading [[cause of death]] in the U.S. and caused 24.95% of total deaths in 2008.<ref>{{cite journal|last1=Pagidipati|first1=Neha Jadeja|last2=Gaziano|first2=Thomas A.|title=Estimating Deaths From Cardiovascular Disease: A Review of Global Methodologies of Mortality Measurement|journal=Circulation|date= 2013|volume=127|issue=6|pages=749–756| doi=10.1161/CIRCULATIONAHA.112.128413|pmid=23401116|language=en|issn=0009-7322|pmc=3712514}}</ref>

The primary responsibility of the heart is to pump blood throughout the body.
It pumps blood from the body — called the [[systemic circulation]] — through the [[lung]]s — called the [[pulmonary circulation]] — and then back out to the body. This means that the heart is connected to and affects the entirety of the body. Simplified, the heart is a circuit of the [[Circulatory system|circulation]].<ref>{{cite web |title=How the Heart Works |url=https://www.nhlbi.nih.gov/health/heart/blood-flow |website=NHLBI |date=24 March 2022 |publisher=National Heart, Lung, and Blood Institute |access-date=28 February 2025}}</ref> While plenty is known about the healthy heart, the bulk of study in cardiology is in disorders of the heart and restoration, and where possible, of function.

The heart is a muscle that squeezes blood and functions like a pump. The heart's systems can be classified as either electrical or mechanical, and both of these systems are susceptible to failure or dysfunction.

The electrical system of the heart is centered on the periodic contraction (squeezing) of the [[myocardium|muscle cells]] that is caused by the [[cardiac pacemaker]] located in the [[sinoatrial node]].
The study of the electrical aspects is a sub-field of [[electrophysiology]] called [[cardiac electrophysiology]] and is epitomized with the electrocardiogram (ECG/EKG).
The [[action potential]]s generated in the pacemaker propagate throughout the heart in a specific pattern. The system that carries this potential is called the [[electrical conduction system of the heart|electrical conduction system]].
Dysfunction of the electrical system manifests in many ways and may include [[Wolff–Parkinson–White syndrome]], [[ventricular fibrillation]], and [[heart block]].<ref>{{Citation|last1=Kashou|first1=Anthony H.|title=Physiology, Sinoatrial Node|date=2021|url=http://www.ncbi.nlm.nih.gov/books/NBK459238/|work=StatPearls|place=Treasure Island (FL)|publisher=StatPearls Publishing|pmid=29083608|access-date=2021-04-22|last2=Basit|first2=Hajira|last3=Chhabra|first3=Lovely}}</ref>

The mechanical system of the heart is centered on the [[fluid mechanics|fluidic movement]] of blood and the functionality of the heart as a [[pump]].
The mechanical part is ultimately the purpose of the heart and many of the disorders of the heart disrupt the ability to move blood.
[[Heart failure]] is one condition in which the mechanical properties of the heart have failed or are failing, which means insufficient blood is being circulated. Failure to move a sufficient amount of blood through the body can cause damage or failure of other organs and may result in death if severe.<ref>{{Cite book|last1=Mebazaa|first1=Alexandre|url=https://books.google.com/books?id=1YSFaSXeE3AC&q=Heart+failure+is+one+condition+in+which+the+mechanical+properties+of+the+heart+have+failed+or+are+failing,+which+means+insufficient+blood+is+being+circulated|title=Acute Heart Failure|last2=Gheorghiade|first2=Mihai|last3=Zannad|first3=Faiez|last4=Parrillo|first4=Joseph E.|date=2009-12-24|publisher=Springer Science & Business Media|isbn=978-1-84628-782-4|language=en}}</ref>

=== Coronary circulation ===
{{Main|Coronary circulation}}

Coronary circulation is the circulation of blood in the [[blood vessel]]s of the [[heart muscle]] (the myocardium). The vessels that deliver oxygen-rich blood to the myocardium are known as coronary arteries. The vessels that remove the deoxygenated blood from the heart muscle are known as cardiac veins. These include the [[great cardiac vein]], the [[middle cardiac vein]], the [[small cardiac vein]] and the [[anterior cardiac veins]].

As the left and right coronary arteries run on the surface of the heart, they can be called epicardial coronary arteries. These arteries, when healthy, are capable of autoregulation to maintain coronary blood flow at levels appropriate to the needs of the heart muscle. These relatively narrow vessels are commonly affected by [[atherosclerosis]] and can become blocked, causing [[Angina pectoris|angina]] or myocardial infarction (a.k.a., a heart attack). The coronary arteries that run deep within the myocardium are referred to as subendocardial.

The coronary arteries are classified as "end circulation", since they represent the only source of blood supply to the myocardium; there is very little redundant blood supply, which is why blockage of these vessels can be so critical.

=== Cardiac examination ===
{{Main|Cardiac examination}}

The cardiac examination (also called the "precordial exam"), is performed as part of a [[physical examination]], or when a patient presents with [[chest pain]] suggestive of a cardiovascular [[pathology]]. It would typically be modified depending on the [[Indication (medicine)|indication]] and integrated with other examinations especially the [[respiratory examination]].<ref>{{Cite journal |last=Maher |first=Toby M. |date=2012-11-01 |title=A Clinical Approach to Diffuse Parenchymal Lung Disease |url=https://www.sciencedirect.com/science/article/abs/pii/S088985611200104X |journal=Immunology and Allergy Clinics of North America |series=Interstitial Lung Disease and Autoimmune Lung Diseases |volume=32 |issue=4 |pages=453–472 |doi=10.1016/j.iac.2012.08.004 |pmid=23102061 |issn=0889-8561|url-access=subscription }}</ref>

Like all medical examinations, the cardiac examination follows the standard structure of inspection, palpation and auscultation.<ref>According to the University of California, San Francisco, a comprehensive cardiac examination involves these three critical steps: inspection, palpation, and auscultation. This process helps in evaluating the heart's condition by first observing for visible signs, then feeling for abnormalities, and finally listening to the heart sounds.</ref><ref>Similarly, Chamberlain University outlines that the cardiac examination starts with inspection to identify any visual anomalies, followed by palpation to assess physical findings such as thrills or heaves, and concludes with auscultation to detect any abnormal heart sounds like murmurs or gallops.</ref>

== Heart disorders ==
{{Main|List of heart disorders}}

Cardiology is concerned with the normal functionality of the heart and the deviation from a healthy heart. Many disorders involve the heart itself, but some are outside of the heart and in the vascular system. Collectively, the two are jointly termed the cardiovascular system, and diseases of one part tend to affect the other.

=== Coronary artery disease ===
{{Main|Coronary artery disease}}

Coronary artery disease, also known as "ischemic heart disease",<ref>{{cite book|last=Bhatia|first=Sujata K.|title=Biomaterials for clinical applications|year=2010|publisher=Springer|location=New York|isbn=9781441969200|page=23|url=https://books.google.com/books?id=bXtaX468LRYC&pg=PA23|edition=Online-Ausg.}}</ref> is a group of diseases that includes: [[stable angina]], [[unstable angina]], myocardial infarction, and is one of the causes of [[sudden cardiac death]].<ref name=Wong2014>{{cite journal|last1=Wong|first1=ND|title=Epidemiological studies of CHD and the evolution of preventive cardiology.|journal=Nature Reviews. Cardiology|date=May 2014|volume=11|issue=5|pages=276–89|pmid=24663092|doi=10.1038/nrcardio.2014.26|s2cid=9327889}}</ref> It is within the group of cardiovascular diseases of which it is the most common type.<ref name="pmid25530442"/> A common symptom is [[chest pain]] or discomfort which may travel into the shoulder, arm, back, neck, or jaw.<ref name=HLB2014/> Occasionally it may feel like [[heartburn]]. Usually symptoms occur with exercise or emotional [[Stress (psychological)|stress]], last less than a few minutes, and get better with rest.<ref name=HLB2014/> [[Shortness of breath]] may also occur and sometimes no symptoms are present.<ref name=HLB2014>{{cite web|title=What Are the Signs and Symptoms of Coronary Heart Disease?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/cad/signs|access-date=23 February 2015|date=29 September 2014|archive-url=https://web.archive.org/web/20150224034615/http://www.nhlbi.nih.gov/health/health-topics/topics/cad/signs|archive-date=24 February 2015|url-status=dead}}</ref> The first sign is occasionally a heart attack.<ref name=CDC2013/> Other complications include [[heart failure]] or an [[Heart arrhythmia|irregular heartbeat]].<ref name=CDC2013>{{cite web|title=Coronary Artery Disease (CAD)|url=https://www.cdc.gov/heartdisease/coronary_ad.htm|access-date=23 February 2015|date=12 March 2013|archive-url=https://web.archive.org/web/20150302152003/http://www.cdc.gov/heartdisease/coronary_ad.htm|archive-date=2 March 2015|url-status=dead}}</ref>

<!--Cause and diagnosis -->
Risk factors include: [[hypertension|high blood pressure]], [[tobacco smoking|smoking]], [[diabetes mellitus|diabetes]], lack of exercise, [[obesity]], [[hypercholesterolaemia|high blood cholesterol]], poor diet, and excessive [[ethanol|alcohol]], among others.<ref>{{cite journal|last1=Mehta|first1=PK|last2=Wei|first2=J|last3=Wenger|first3=NK|title=Ischemic heart disease in women: A focus on risk factors|journal=Trends in Cardiovascular Medicine|date=16 October 2014|pmid=25453985|doi=10.1016/j.tcm.2014.10.005|volume=25|issue=2|pages=140–151|pmc=4336825}}</ref><ref name=WHO2011b>{{cite book|last1=Mendis|first1=Shanthi|last2=Puska|first2=Pekka|last3=Norrving|first3=Bo|title=Global atlas on cardiovascular disease prevention and control|date=2011|publisher=World Health Organization in collaboration with the World Heart Federation and the World Stroke Organization|location=Geneva|isbn=9789241564373|pages=3–18|edition=1st|url=http://whqlibdoc.who.int/publications/2011/9789241564373_eng.pdf?ua=1}}</ref> Other risks include [[major depressive disorder|depression]].<ref>{{cite journal|last1=Charlson|first1=FJ|last2=Moran|first2=AE|last3=Freedman|first3=G|last4=Norman|first4=RE|last5=Stapelberg|first5=NJ|last6=Baxter|first6=AJ|last7=Vos|first7=T|last8=Whiteford|first8=HA|title=The contribution of major depression to the global burden of ischemic heart disease: a comparative risk assessment|journal=BMC Medicine|date=26 November 2013|volume=11|page=250|pmid=24274053|doi=10.1186/1741-7015-11-250|pmc=4222499 |doi-access=free }}</ref> The underlying mechanism involves [[atherosclerosis]] of the [[Coronary circulation|arteries of the heart]]. A number of tests may help with diagnoses including: electrocardiogram, [[cardiac stress test]]ing, [[coronary computed tomographic angiography]], and [[Coronary catheterization|coronary angiogram]], among others.<ref>{{cite web|title=How Is Coronary Heart Disease Diagnosed?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/cad/diagnosis|access-date=25 February 2015|date=29 September 2014}}</ref>

<!-- Prevention and treatment -->
Prevention is by eating a healthy diet, regular exercise, maintaining a healthy weight and not smoking.<ref name=HLB2013P/> Sometimes medication for diabetes, high cholesterol, or high blood pressure are also used.<ref name=HLB2013P>{{cite web|title=How Can Coronary Heart Disease Be Prevented or Delayed?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/cad/prevention|access-date=25 February 2015}}</ref> There is limited evidence for screening people who are at low risk and do not have symptoms.<ref>{{cite journal|last1=Desai|first1=CS|last2=Blumenthal|first2=RS|last3=Greenland|first3=P|title=Screening low-risk individuals for coronary artery disease|journal=Current Atherosclerosis Reports|date=April 2014|volume=16|issue=4|page=402|pmid=24522859|doi=10.1007/s11883-014-0402-8|s2cid=39392260}}</ref> Treatment involves the same measures as prevention.<ref>{{cite journal|last1=Boden|first1=WE|last2=Franklin|first2=B|last3=Berra|first3=K|last4=Haskell|first4=WL|last5=Calfas|first5=KJ|last6=Zimmerman|first6=FH|last7=Wenger|first7=NK|title=Exercise as a therapeutic intervention in patients with stable ischemic heart disease: an underfilled prescription.|journal=The American Journal of Medicine|date=October 2014|volume=127|issue=10|pages=905–11|pmid=24844736|doi=10.1016/j.amjmed.2014.05.007}}</ref><ref name=HLB2013Tr/> Additional medications such as [[antiplatelet drug|antiplatelets]] including [[aspirin]], [[beta blocker]]s, or [[Medical use of nitroglycerin|nitroglycerin]] may be recommended.<ref name=HLB2013Tr/> Procedures such as [[percutaneous coronary intervention]] (PCI) or [[coronary artery bypass surgery]] (CABG) may be used in severe disease.<ref name=HLB2013Tr>{{cite web|title=How Is Coronary Heart Disease Treated?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/cad/treatment|access-date=25 February 2015|date=29 September 2014}}</ref><ref>{{cite journal|last1=Deb|first1=S|last2=Wijeysundera|first2=HC|last3=Ko|first3=DT|last4=Tsubota|first4=H|last5=Hill|first5=S|last6=Fremes|first6=SE|title=Coronary artery bypass graft surgery vs percutaneous interventions in coronary revascularization: a systematic review.|journal=JAMA|date=20 November 2013|volume=310|issue=19|pages=2086–95|pmid=24240936|doi=10.1001/jama.2013.281718|doi-access=free}}</ref> In those with stable CAD it is unclear if PCI or CABG in addition to the other treatments improve [[life expectancy]] or decreases heart attack risk.<ref>{{cite journal|last1=Rezende|first1=PC|last2=Scudeler|first2=TL|last3=da Costa|first3=LM|last4=Hueb|first4=W|title=Conservative strategy for treatment of stable coronary artery disease|journal=World Journal of Clinical Cases|date=16 February 2015|volume=3|issue=2|pages=163–70|pmid=25685763|doi=10.12998/wjcc.v3.i2.163|pmc=4317610 |doi-access=free }}</ref>

<!--Epidemiology  -->
In 2013 CAD was the [[most common causes of death|most common cause of death]] globally, resulting in 8.14 million deaths (16.8%) up from 5.74 million deaths (12%) in 1990.<ref name="pmid25530442">{{cite journal | vauthors = ((GBD 2013 Mortality and Causes of Death Collaborators))| title = Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013 | journal = Lancet | volume = 385 | issue = 9963 | pages = 117–71 | date = January 2015 | pmid = 25530442 | pmc = 4340604 | doi = 10.1016/S0140-6736(14)61682-2 }}</ref> The risk of death from CAD for a given age has decreased between 1980 and 2010 especially in [[developed country|developed countries]].<ref>{{cite journal|last1=Moran|first1=AE|last2=Forouzanfar|first2=MH|last3=Roth|first3=GA|last4=Mensah|first4=GA|last5=Ezzati|first5=M|last6=Murray|first6=CJ|last7=Naghavi|first7=M|title=Temporal trends in ischemic heart disease mortality in 21 world regions, 1980 to 2010: the Global Burden of Disease 2010 study|journal=Circulation|date=8 April 2014|volume=129|issue=14|pages=1483–92|pmid=24573352|doi=10.1161/circulationaha.113.004042|pmc=4181359}}</ref> The number of cases of CAD for a given age has also decreased between 1990 and 2010.<ref>{{cite journal|last1=Moran|first1=AE|last2=Forouzanfar|first2=MH|last3=Roth|first3=GA|last4=Mensah|first4=GA|last5=Ezzati|first5=M|last6=Flaxman|first6=A|last7=Murray|first7=CJ|last8=Naghavi|first8=M|title=The global burden of ischemic heart disease in 1990 and 2010: the Global Burden of Disease 2010 study|journal=Circulation|date=8 April 2014|volume=129|issue=14|pages=1493–501|pmid=24573351|doi=10.1161/circulationaha.113.004046|pmc=4181601}}</ref> In the U.S. in 2010 about 20% of those over 65 had CAD, while it was present in 7% of those 45 to 64, and 1.3% of those 18 to 45.<ref name=US2011/> Rates are higher among men than women of a given age.<ref name=US2011>{{cite journal|last1=Centers for Disease Control and Prevention|first1=(CDC)|title=Prevalence of coronary heart disease—United States, 2006–2010.|journal=MMWR. Morbidity and Mortality Weekly Report|date=14 October 2011|volume=60|issue=40|pages=1377–81|pmid=21993341}}</ref>

===Cardiomyopathy===
{{main|Cardiomyopathy}}
{{expand section|date=November 2021}}

Heart failure, or formally cardiomyopathy, is the impaired function of the heart, and there are numerous causes and forms of heart failure.

The causes of cardiomyopathy can be [[Genetic disorder|genetic]], viral, or lifestyle-related. Key symptoms of cardiomyopathy include shortness of breath, fatigue, and irregular heartbeats. Understanding the specific function of cardiac muscle is crucial, as the heart muscle's main role is to pump blood throughout the body efficiently.<ref>"[https://atriuscardiac.care/blogs/comprehensive-guide-to-understanding-cardiomyopathy/ Comprehensive Guide to Understanding and Managing Cardiomyopathy]" by [https://atriuscardiac.care/ Atrius Cardiac Care]</ref>

===Cardiac arrhythmia===
{{Main|Arrhythmia}}

Cardiac arrhythmia, also known as "cardiac dysrhythmia" or "irregular heartbeat", is a group of conditions in which the [[Cardiac cycle|heartbeat]] is too fast, too slow, or irregular in its rhythm.<!-- <ref name=NIH2011Def/> --> A [[heart rate]] that is too fast – above 100 beats per minute in adults – is called [[tachycardia]]. A heart rate that is too slow – below 60 beats per minute – is called [[bradycardia]].<ref name="NIH2011Def">{{cite web|title=What Is Arrhythmia?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/arr|website=www.nhlbi.nih.gov|access-date=7 March 2015|date=July 1, 2011|archive-url=https://web.archive.org/web/20150302074103/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/|archive-date=2 March 2015|url-status=dead}}</ref> Many types of arrhythmia present no symptoms.<!-- <ref name=NIH2011Sym-a/> --> When symptoms are present, they may include [[palpitations]], or feeling a pause between heartbeats.<!-- <ref name=NIH2011Sym-a/> --> More serious symptoms may include [[presyncope|lightheadedness]], [[Syncope (medicine)|passing out]], [[shortness of breath]], or [[chest pain]].<ref name="NIH2011Sym-a">{{cite web|title=What Are the Signs and Symptoms of an Arrhythmia?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/arr/signs|website=www.nhlbi.nih.gov|access-date=7 March 2015|date=July 1, 2011|archive-url=https://web.archive.org/web/20150219081446/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/signs|archive-date=19 February 2015|url-status=dead}}</ref> While most types of arrhythmia are not serious, some predispose a person to complications such as [[stroke]] or [[heart failure]].<ref name="NIH2011Def" /><ref name="NIH2011Type" /> Others may result in [[cardiac arrest]].<ref name="NIH2011Type" />

<!-- Cause and diagnosis -->
There are four main types of arrhythmia: [[premature heart beat|extra beats]], [[supraventricular tachycardia]]s, [[ventricular arrhythmia]]s, and [[bradyarrhythmia]]s.<!-- <ref name=NIH2011Type/> --> Extra beats include [[premature atrial contraction]]s, [[premature ventricular contraction]]s, and [[premature junctional contractions]].<!-- <ref name=NIH2011Type/> --> Supraventricular tachycardias include [[atrial fibrillation]], [[atrial flutter]], and [[paroxysmal supraventricular tachycardia]].<!-- <ref name=NIH2011Type/> --> Ventricular arrhythmias include [[ventricular fibrillation]] and [[ventricular tachycardia]].<ref name="NIH2011Type">{{cite web|title=Types of Arrhythmia|url=http://www.nhlbi.nih.gov/health/health-topics/topics/arr/types|website=www.nhlbi.nih.gov|access-date=7 March 2015|date=July 1, 2011|archive-url=https://web.archive.org/web/20150607165144/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/types|archive-date=7 June 2015|url-status=dead}}</ref><ref name="Martin2012">{{cite journal|last1=Martin|first1=C|last2=Matthews|first2=G|last3=Huang|first3=CL|title=Sudden cardiac death and Inherited channelopathy: the basic electrophysiology of the myocyte and myocardium in ion channel disease|journal=Heart|date=2012|volume=98|issue=7|pages=536–543|pmid=22422742|doi=10.1136/heartjnl-2011-300953|pmc=3308472}}</ref> Arrhythmias are due to problems with the [[electrical conduction system of the heart]].<ref name="NIH2011Def" /> Arrhythmias may occur in children; however, the normal range for the heart rate is different and depends on age.<ref name="NIH2011Type" /> A number of tests can help diagnose arrhythmia, including an electrocardiogram and [[Holter monitor]].<ref>{{cite web|title=How Are Arrhythmias Diagnosed?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/arr/diagnosis|website=www.nhlbi.nih.gov/|access-date=7 March 2015|date=July 1, 2011|archive-url=https://web.archive.org/web/20150218075708/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/diagnosis|archive-date=18 February 2015|url-status=dead}}</ref>

<!-- Treatment -->
Most arrhythmias can be effectively treated.<ref name=NIH2011Def/> Treatments may include medications, medical procedures such as a [[pacemaker]], and surgery.<!-- <ref name=NIH2011Tx-Arrhythmias/> --> Medications for a fast heart rate may include [[beta blockers]] or [[antiarrhythmic agent|agents that attempt to restore a normal heart rhythm]] such as [[procainamide]].<!-- <ref name=NIH2011Tx-Arrhythmias/> --> This later group may have more significant side effects especially if taken for a long period of time.<!-- <ref name=NIH2011Tx-Arrhythmias/> --> Pacemakers are often used for slow heart rates.<!-- <ref name=NIH2011Tx-Arrhythmias/> --> Those with an irregular heartbeat are often treated with [[blood thinner]]s to reduce the risk of complications.<!-- <ref name=NIH2011Tx-Arrhythmias/> --> Those who have severe symptoms from an arrhythmia may receive urgent treatment with a jolt of electricity in the form of [[cardioversion]] or [[defibrillation]].<ref name=NIH2011Tx-Arrhythmias>{{cite web|title=How Are Arrhythmias Treated?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/arr/treatment|website=www.nhlbi.nih.gov/|access-date=7 March 2015|date=July 1, 2011|archive-url=https://web.archive.org/web/20150217135319/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/treatment|archive-date=17 February 2015|url-status=dead}}</ref>

<!-- Epidemiology -->
Arrhythmia affects millions of people.<ref name=NIH2011Risk>{{cite web|title=Who Is at Risk for an Arrhythmia?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/arr/atrisk|website=www.nhlbi.nih.gov/|access-date=7 March 2015|date=July 1, 2011|archive-url=https://web.archive.org/web/20150303190136/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/atrisk|archive-date=3 March 2015|url-status=dead}}</ref> In Europe and North America, as of 2014, atrial fibrillation affects about 2% to 3% of the population.<ref name=Zoni2014>{{cite journal|last1=Zoni-Berisso|first1=M|last2=Lercari|first2=F|last3=Carazza|first3=T|last4=Domenicucci|first4=S|title=Epidemiology of atrial fibrillation: European perspective|journal=Clinical Epidemiology|date=2014|volume=6|pages=213–20|pmid=24966695|doi=10.2147/CLEP.S47385|pmc=4064952|doi-access=free}}</ref> Atrial fibrillation and atrial flutter resulted in 112,000 deaths in 2013, up from 29,000 in 1990.<ref name="pmid25530442"/> [[Sudden cardiac death]] is the cause of about half of deaths due to cardiovascular disease or about 15% of all deaths globally.<ref name=Meh2007>{{cite journal|last1=Mehra|first1=R|title=Global public health problem of sudden cardiac death|journal=[[Journal of Electrocardiology]]|date=2007|volume=40|issue=6 Suppl|pages=S118–22|pmid=17993308|doi=10.1016/j.jelectrocard.2007.06.023}}</ref> About 80% of sudden cardiac death is the result of ventricular arrhythmias.<ref name=Meh2007/> Arrhythmias may occur at any age but are more common among older people.<ref name=NIH2011Risk/>

=== Cardiac arrest ===
{{Main|Cardiac arrest}}

Cardiac arrest is a sudden stop in effective [[circulatory system|blood flow]] due to the failure of the heart to contract effectively.<ref name=NIH2016What/> Symptoms include [[unconsciousness|loss of consciousness]] and [[respiratory arrest|abnormal or absent breathing]].<ref name=Fie2009>{{cite book|last1=Field|first1=John M.|title=The Textbook of Emergency Cardiovascular Care and CPR|date=2009|publisher=Lippincott Williams & Wilkins|isbn=9780781788991|page=11|url=https://books.google.com/books?id=JaOoXdSlT9sC&pg=PA11|language=en}}</ref><ref name=NIH2016Sign/> Some people may have [[chest pain]], [[shortness of breath]], or [[nausea]] before this occurs.<ref name=NIH2016Sign>{{cite web|title=What Are the Signs and Symptoms of Sudden Cardiac Arrest?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/scda/signs|website=NHLBI|access-date=16 August 2016|date=June 22, 2016}}</ref> If not treated within minutes, [[death]] usually occurs.<ref name=NIH2016What>{{cite web|title=What Is Sudden Cardiac Arrest?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/scda|website=NHLBI|access-date=16 August 2016|date=June 22, 2016}}</ref>

<!-- Cause and diagnosis -->
The most common cause of cardiac arrest is [[coronary artery disease]].<!-- <ref name=NIH2016Ca/> --> Less common causes include [[bleeding|major blood loss]], lack of oxygen, [[hypokalemia|very low potassium]], [[heart failure]], and intense physical exercise.<!-- <ref name=NIH2016Ca/> --> A number of inherited disorders may also increase the risk including [[long QT syndrome]].<!-- <ref name=NIH2016Ca/> --> The initial heart rhythm is most often [[ventricular fibrillation]].<ref name=NIH2016Ca>{{cite web|title=What Causes Sudden Cardiac Arrest?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/scda/causes|website=NHLBI|access-date=16 August 2016|date=June 22, 2016}}</ref> The diagnosis is confirmed by finding no pulse.<ref name=Fie2009/> While a cardiac arrest may be caused by heart attack or heart failure these are not the same.<ref name=NIH2016What/>

<!-- Treatment and prognosis -->
Prevention includes not smoking, physical activity, and maintaining a healthy weight.<ref name=NIH2016Pre/> Treatment for cardiac arrest is immediate [[cardiopulmonary resuscitation]] (CPR) and, if a [[shockable rhythm]] is present, [[defibrillation]].<ref name=NIH2016Tx>{{cite web|title=How Is Sudden Cardiac Arrest Treated?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/scda/treatment|website=NHLBI|access-date=16 August 2016|date=June 22, 2016}}</ref> Among those who survive [[targeted temperature management]] may improve outcomes.<ref name="pmid27521472">{{cite journal | vauthors = Schenone AL, Cohen A, Patarroyo G, Harper L, Wang X, Shishehbor MH, Menon V, Duggal A | title = Therapeutic hypothermia after cardiac arrest: A systematic review/meta-analysis exploring the impact of expanded criteria and targeted temperature | journal = Resuscitation | volume = 108 | issue = | pages = 102–110 | date = November 2016 | pmid = 27521472 | doi = 10.1016/j.resuscitation.2016.07.238 }}</ref> An [[implantable cardiac defibrillator]] may be placed to reduce the chance of death from recurrence.<ref name=NIH2016Pre>{{cite web|title=How Can Death Due to Sudden Cardiac Arrest Be Prevented?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/scda/prevention|website=NHLBI|access-date=16 August 2016|date=June 22, 2016}}</ref>

<!-- Epidemiology and history -->
In the [[United States]], cardiac arrest outside of [[hospital]] occurs in about 13 per 10,000 people per year (326,000 cases). In hospital cardiac arrest occurs in an additional 209,000<ref name="pmid26472992">{{cite journal | vauthors = Kronick SL, Kurz MC, Lin S, Edelson DP, Berg RA, Billi JE, Cabanas JG, Cone DC, Diercks DB, Foster JJ, Meeks RA, Travers AH, Welsford M | title = Part 4: Systems of Care and Continuous Quality Improvement: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care | journal = Circulation | volume = 132 | issue = 18 Suppl 2 | pages = S397–413 | date = November 2015 | pmid = 26472992 | doi = 10.1161/CIR.0000000000000258 |doi-access=free}}</ref> Cardiac arrest becomes more common with age.<!-- <ref name=NIH2016Risk/> --> It affects males more often than females.<ref name=NIH2016Risk>{{cite web|title=Who Is at Risk for Sudden Cardiac Arrest?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/scda/atrisk|website=NHLBI|access-date=16 August 2016|date=June 22, 2016}}</ref> The percentage of people who survive with treatment is about 8%.<!-- <ref name=Adam2012/> --> Many who survive have significant [[disability]].<!-- <ref name=Adam2012/> --> Many U.S. television shows, however, have portrayed unrealistically high survival rates of 67%.<ref name=Adam2012>{{cite book|last1=Adams|first1=James G.|title=Emergency Medicine: Clinical Essentials (Expert Consult – Online)|date=2012|publisher=Elsevier Health Sciences|isbn=978-1455733941|page=1771|url=https://books.google.com/books?id=rpoH-KYE93IC&pg=PA1771|language=en}}</ref>

=== Hypertension ===
{{Main|Hypertension}}

[[Hypertension]], also known as "high blood pressure", is a [[Chronic (medicine)|long term]] [[Disease|medical condition]] in which the [[blood pressure]] in the [[artery|arteries]] is persistently elevated.<ref name=Nai2014>{{cite book|last1=Naish|first1=Jeannette|last2=Court|first2=Denise Syndercombe|title=Medical sciences|date=2014|isbn=9780702052491|page=562|publisher=Elsevier Health Sciences |edition=2|url=https://books.google.com/books?id=K21_AwAAQBAJ&pg=PA562}}</ref> High blood pressure usually does not cause symptoms.<ref name=CDC2015>{{cite web|title=High Blood Pressure Fact Sheet|url=https://www.cdc.gov/dhdsp/data_statistics/fact_sheets/fs_bloodpressure.htm|website=CDC|access-date=6 March 2016|date=February 19, 2015}}</ref> Long term high blood pressure, however, is a major risk factor for [[coronary artery disease]], [[stroke]], [[heart failure]], [[peripheral vascular disease]], [[vision loss]], and [[chronic kidney disease]].<ref>{{cite journal|last1=Lackland|first1=DT|last2=Weber|first2=MA|title=Global burden of cardiovascular disease and stroke: hypertension at the core|journal=The Canadian Journal of Cardiology|date=May 2015|volume=31|issue=5|pages=569–71|pmid=25795106|doi=10.1016/j.cjca.2015.01.009}}</ref><ref name=WHO2011a>{{cite book|last1=Mendis|first1=Shanthi|last2=Puska|first2=Pekka|last3=Norrving|first3=Bo|title=Global atlas on cardiovascular disease prevention and control|date=2011|publisher=World Health Organization in collaboration with the World Heart Federation and the World Stroke Organization|location=Geneva|isbn=9789241564373|page=38|edition=1st|url=http://whqlibdoc.who.int/publications/2011/9789241564373_eng.pdf?ua=1}}</ref>

<!-- Causes -->
Lifestyle factors can increase the risk of hypertension. These include [[Salt and cardiovascular disease|excess salt]] in the diet, [[overweight|excess body weight]], [[smoking]], and alcohol consumption.<ref name=CDC2015/><ref name=Lancet2015/> Hypertension can also be caused by other diseases, or occur as a side-effect of drugs.<ref>{{cite web|url=https://www.nhlbi.nih.gov/health-topics/high-blood-pressure|title=High Blood Pressure|date=8 May 2020|website=[[National Heart, Lung, and Blood Institute]]|access-date=11 October 2021}}</ref>

<!-- Diagnosis -->
Blood pressure is expressed by two measurements, the [[Systole (medicine)|systolic]] and [[diastolic]] pressures, which are the maximum and minimum pressures, respectively.<ref name=CDC2015/> Normal blood pressure when at rest is within the range of 100–140 [[Millimeter of mercury|millimeters mercury]] (mmHg) systolic and 60–90 mmHg diastolic.<ref name="EU2013">{{cite journal|last1 = Giuseppe|first1 = Mancia|title = 2013 ESH/ESC Guidelines for the management of arterial hypertension: The Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC)|journal = European Heart Journal|date = July 2013|volume = 34|issue = 28|pages = 2159–219|pmid = 23771844|doi = 10.1093/eurheartj/eht151|first2 = R|last3 = Narkiewicz|first3 = K|last4 = Redon|first4 = J|last5 = Zanchetti|first5 = A|last6 = Bohm|first6 = M|last7 = Christiaens|first7 = T|last8 = Cifkova|first8 = R|last9 = De Backer|first9 = G|last10 = Dominiczak|first10 = A|last11 = Galderisi|first11 = M|last12 = Grobbee|first12 = DE|last13 = Jaarsma|first13 = T|last14 = Kirchhof|first14 = P|last15 = Kjeldsen|first15 = SE|last16 = Laurent|first16 = S|last17 = Manolis|first17 = AJ|last18 = Nilsson|first18 = PM|last19 = Ruilope|first19 = LM|last20 = Schmieder|first20 = RE|last21 = Sirnes|first21 = PA|last22 = Sleight|first22 = P|last23 = Viigimaa|first23 = M|last24 = Waeber|first24 = B|last25 = Zannad|first25 = F|last26 = Redon|first26 = J|last27 = Dominiczak|first27 = A|last28 = Narkiewicz|first28 = K|last29 = Nilsson|first29 = PM|last30 = Burnier|first30 = M|last2 = Fagard|display-authors = 29|hdl = 1854/LU-4127523|url = https://academic.oup.com/eurheartj/article-pdf/34/28/2159/17895598/eht151.pdf}}</ref> High blood pressure is present if the resting blood pressure is persistently at or above 140/90 mmHg for most adults.<ref name=Lancet2015/> Different numbers apply to children.<ref name=JNC8>{{Cite journal  |last1 = James|first1 = PA.|last2 = Oparil|first2 = S.|last3 = Carter|first3 = BL.|last4 = Cushman|first4 = WC.|last5 = Dennison-Himmelfarb|first5 = C.|last6 = Handler|first6 = J.|last7 = Lackland|first7 = DT.|last8 = Lefevre|first8 = ML.|last9 = Mackenzie|first9 = TD.|last10 = Ogedegbe|first10 = Olugbenga|last11 = Smith|first11 = Sidney C.|last12 = Svetkey|first12 = Laura P.|last13 = Taler|first13 = Sandra J.|last14 = Townsend|first14 = Raymond R.|last15 = Wright|first15 = Jackson T.|last16 = Narva|first16 = Andrew S.|last17 = Ortiz|first17 = Eduardo|title = 2014 Evidence-Based Guideline for the Management of High Blood Pressure in Adults: Report From the Panel Members Appointed to the Eighth Joint National Committee (JNC 8)|journal = JAMA|volume = 311|issue = 5|pages = 507–20|date = Dec 2013|doi = 10.1001/jama.2013.284427|pmid = 24352797|display-authors = 8|doi-access = free}}</ref> When diagnosing high blood pressure, [[ambulatory blood pressure monitoring]] over a 24-hour period appears to be more accurate than "in-office" [[blood pressure measurement]] at a physician's office or other blood pressure screening location.<ref name=Nai2014/><ref name=Lancet2015/><ref name="Stergiou-Kollias">{{cite journal | last1=Stergiou | first1=George | last2=Kollias | first2=Anastasios | last3=Parati | first3=Gianfranco | last4=O’Brien | first4=Eoin | title=Office Blood Pressure Measurement | journal=Hypertension | publisher=Ovid Technologies (Wolters Kluwer Health) | volume=71 | issue=5 | year=2018 | issn=0194-911X | pmid=29531176 | doi=10.1161/hypertensionaha.118.10850 | pages=813–815| s2cid=3853179 | doi-access=free }}</ref>

<!-- Treatment and epidemiology -->
Lifestyle changes and medications can lower blood pressure and decrease the risk of health complications.<ref name=NIH2015Tx>{{cite web|title=How Is High Blood Pressure Treated?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/hbp/treatment|website=National Heart, Lung, and Blood Institute|access-date=6 March 2016|date=September 10, 2015}}</ref> Lifestyle changes include weight loss, decreased salt intake, physical exercise, and a healthy diet.<ref name=Lancet2015/> If changes in lifestyle are insufficient, [[blood pressure medication]]s may be used.<ref name=NIH2015Tx/> A regimen of up to three medications effectively controls blood pressure in 90% of people.<ref name=Lancet2015>{{cite journal|last1=Poulter|first1=NR|last2=Prabhakaran|first2=D|last3=Caulfield|first3=M|title=Hypertension.|journal=Lancet|date=22 August 2015|volume=386|issue=9995|pages=801–12|pmid=25832858|doi=10.1016/s0140-6736(14)61468-9|s2cid=208792897}}</ref> The treatment of moderate to severe high arterial blood pressure (defined as >160/100 mmHg) with medication is associated with an improved [[life expectancy]] and reduced [[morbidity]].<ref>{{Cite journal|last1=Musini|first1=Vijaya M|last2=Tejani|first2=Aaron M|last3=Bassett|first3=Ken|last4=Puil|first4=Lorri|last5=Wright|first5=James M|date=2019-06-05|editor-last=Cochrane Hypertension Group|title=Pharmacotherapy for hypertension in adults 60 years or older|journal=Cochrane Database of Systematic Reviews|volume=6|issue=6 |pages=CD000028|language=en|doi=10.1002/14651858.CD000028.pub3|pmid=31167038|pmc=6550717}}</ref> The effect of treatment for blood pressure between 140/90&nbsp;mmHg and 160/100&nbsp;mmHg is less clear, with some studies finding benefits<ref>{{cite journal|last1=Sundström|first1=Johan|last2=Arima|first2=Hisatomi|last3=Jackson|first3=Rod|last4=Turnbull|first4=Fiona|last5=Rahimi|first5=Kazem|last6=Chalmers|first6=John|last7=Woodward|first7=Mark|last8=Neal|first8=Bruce|title=Effects of Blood Pressure Reduction in Mild Hypertension|journal=Annals of Internal Medicine|date=February 2015|pmid=25531552|doi=10.7326/M14-0773|volume=162|issue=3|pages=184–91}}</ref><ref>{{cite journal|last1=Xie|first1=X|last2=Atkins|first2=E|last3=Lv|first3=J|last4=Bennett|first4=A|last5=Neal|first5=B|last6=Ninomiya|first6=T|last7=Woodward|first7=M|last8=MacMahon|first8=S|last9=Turnbull|first9=F|last10=Hillis|first10=GS|last11=Chalmers|first11=J|last12=Mant|first12=J|last13=Salam|first13=A|last14=Rahimi|first14=K|last15=Perkovic|first15=V|last16=Rodgers|first16=A|title=Effects of intensive blood pressure lowering on cardiovascular and renal outcomes: updated systematic review and meta-analysis|journal=Lancet|date=30 January 2016|pmid=26559744|doi=10.1016/S0140-6736(15)00805-3|volume=387 |issue=10017|pages=435–43|s2cid=36805676|url=http://www.med-sovet.pro/jour/article/view/1765|url-access=subscription}}</ref> while others do not.<ref name=Diao2012>{{cite journal|last1=Diao|first1=D|last2=Wright|first2=JM|last3=Cundiff|first3=DK|last4=Gueyffier|first4=F|title=Pharmacotherapy for mild hypertension|journal=The Cochrane Database of Systematic Reviews|date=Aug 15, 2012|volume=8|issue=8|pages=CD006742|pmid=22895954|doi=10.1002/14651858.CD006742.pub2|pmc=8985074}}</ref> High blood pressure affects between 16% and 37% of the population globally.<ref name=Lancet2015/> In 2010, hypertension was believed to have been a factor in 18% (9.4 million) deaths.<ref>{{cite journal|last1=Campbell|first1=NR|last2=Lackland|first2=DT|last3=Lisheng|first3=L|last4=Niebylski|first4=ML|last5=Nilsson|first5=PM|last6=Zhang|first6=XH|title=Using the Global Burden of Disease study to assist development of nation-specific fact sheets to promote prevention and control of hypertension and reduction in dietary salt: a resource from the World Hypertension League|journal=Journal of Clinical Hypertension|date=March 2015|volume=17|issue=3|pages=165–67|pmid=25644474|doi=10.1111/jch.12479|pmc=8031937|s2cid=206028313}}</ref>

==== Essential vs Secondary hypertension ====
{{Main|Essential hypertension|Secondary hypertension}}

Essential hypertension is the form of [[hypertension]] that by definition has no identifiable cause. It is the most common type of hypertension, affecting 95% of hypertensive patients,<ref name="pmid10645931-a">{{cite journal |vauthors=Carretero OA, Oparil S |title=Essential hypertension. Part I: definition and etiology |journal=[[Circulation (journal)|Circulation]] |volume=101 |issue=3 |pages=329–35 |date=January 2000 |pmid=10645931 |doi=10.1161/01.CIR.101.3.329 |doi-access=free }}</ref><ref name="pmid14597461">{{cite journal |vauthors=Oparil S, Zaman MA, Calhoun DA |title=Pathogenesis of hypertension |journal=[[Ann. Intern. Med.]] |volume=139 |issue=9 |pages=761–76 |date=November 2003 |pmid=14597461 |doi= 10.7326/0003-4819-139-9-200311040-00011|s2cid=32785528 }}</ref><ref name="isbn0-7216-0240-1">{{cite book |author1=Hall, John E. |author2=Guyton, Arthur C. |title=Textbook of medical physiology |publisher=Elsevier Saunders |location=St. Louis, Mo |year=2006 |pages=228 |isbn=978-0-7216-0240-0 }}</ref><ref name="urlHypertension: eMedicine Nephrology">{{cite web |url=http://emedicine.medscape.com/article/241381-overview |title=Hypertension: eMedicine Nephrology |access-date=2009-06-05}}</ref> it tends to be familial and is likely to be the consequence of an interaction between [[Environment (biophysical)|environmental]] and [[genetics|genetic]] factors. [[Prevalence]] of essential hypertension increases with [[Ageing|age]], and individuals with relatively high blood pressure at younger ages are at increased risk for the subsequent development of hypertension.
Hypertension can increase the risk of [[cerebrum|cerebral]], [[cardiac]], and [[renal]] events.<ref name="pmid17707755">{{cite journal | vauthors = Messerli FH, Williams B, Ritz E | title = Essential hypertension | journal = Lancet | volume = 370 | issue = 9587 | pages = 591–603 | date = August 2007 | pmid = 17707755 | doi = 10.1016/S0140-6736(07)61299-9 | s2cid = 26414121 }}</ref>

[[Secondary hypertension]] is a type of [[hypertension]] which is caused by an identifiable underlying secondary cause. It is much less common than essential hypertension, affecting only 5% of hypertensive patients. It has many different causes including [[endocrine diseases]], [[kidney diseases]], and [[tumors]]. It also can be a [[Adverse effect|side effect]] of many [[medications]].<ref>{{Cite web |title=Secondary hypertension |url=https://www.mayoclinic.org/diseases-conditions/secondary-hypertension/symptoms-causes/syc-20350679 |access-date=2024-07-21 |website=Mayo Clinic |language=en}}</ref>

==== Complications of hypertension ====
[[Image:Main complications of persistent high blood pressure.svg|thumb|right|250px|Main complications of persistent [[high blood pressure]]]]
{{Main|Complications of hypertension}}

[[Complications of hypertension]] are clinical outcomes that result from [[hypertension|persistent elevation]] of blood pressure.<ref name="pmid19393824">{{cite journal |author=White WB |title=Defining the problem of treating the patient with hypertension and arthritis pain |journal=[[The American Journal of Medicine]] |volume=122 |issue=5 Suppl |pages=S3–9 |date=May 2009 |pmid=19393824 |doi=10.1016/j.amjmed.2009.03.002 }}</ref> Hypertension is a risk factor for all clinical manifestations of [[atherosclerosis]] since it is a risk factor for atherosclerosis itself.<ref name="pmid19110086">{{cite journal |author=Insull W |title=The pathology of atherosclerosis: plaque development and plaque responses to medical treatment |journal=[[The American Journal of Medicine]] |volume=122 |issue=1 Suppl |pages=S3–S14 |date=January 2009 |pmid=19110086 |doi=10.1016/j.amjmed.2008.10.013 }}</ref><ref name="pmid19394559">{{cite journal |vauthors=Liapis CD, Avgerinos ED, Kadoglou NP, Kakisis JD |title=What a vascular surgeon should know and do about atherosclerotic risk factors |journal=[[Journal of Vascular Surgery]] |volume=49 |issue=5 |pages=1348–54 |date=May 2009 |pmid=19394559 |doi=10.1016/j.jvs.2008.12.046 |doi-access=free }}</ref><ref name="pmid19275607">{{cite journal |author=Riccioni G |title=The effect of antihypertensive drugs on carotid intima media thickness: an up-to-date review |journal=[[Current Medicinal Chemistry]] |volume=16 |issue=8 |pages=988–96 |year=2009 |pmid=19275607 |doi=10.2174/092986709787581923 |url=http://www.bentham-direct.org/pages/content.php?CMC/2009/00000016/00000008/0006C.SGM |access-date=2009-06-20 |archive-url=https://archive.today/20130112181214/http://www.bentham-direct.org/pages/content.php?CMC/2009/00000016/00000008/0006C.SGM |archive-date=2013-01-12 |url-status=usurped |url-access=subscription }}</ref><ref name="pmid19138169">{{cite journal |vauthors=Safar ME, Jankowski P |title=Central blood pressure and hypertension: role in cardiovascular risk assessment |journal=[[Clinical Science (journal)|Clinical Science]] |volume=116 |issue=4 |pages=273–82 |date=February 2009 |pmid=19138169 |doi=10.1042/CS20080072 }}</ref><ref name="pmid19124420">{{cite journal | vauthors = Werner CM, Böhm M | title = The therapeutic role of RAS blockade in chronic heart failure | journal = Therapeutic Advances in Cardiovascular Disease | volume = 2 | issue = 3 | pages = 167–77 | date = June 2008 | pmid = 19124420 | doi = 10.1177/1753944708091777 |s2cid = 12972801 |doi-access = free}}</ref> It is an independent predisposing factor for [[heart failure]],<ref name="pmid19427498">{{cite journal |vauthors=Gaddam KK, Verma A, Thompson M, Amin R, Ventura H |title=Hypertension and cardiac failure in its various forms |journal=[[The Medical Clinics of North America]] |volume=93 |issue=3 |pages=665–80 |date=May 2009 |pmid=19427498 |doi=10.1016/j.mcna.2009.02.005 |url=http://journals.elsevierhealth.com/retrieve/pii/S0025-7125(09)00020-0|access-date=2009-06-20|url-access=subscription }}</ref><ref name="pmid19427502">{{cite journal |vauthors=Reisin E, Jack AV |title=Obesity and hypertension: mechanisms, cardio-renal consequences, and therapeutic approaches |journal=[[The Medical Clinics of North America]] |volume=93 |issue=3 |pages=733–51 |date=May 2009 |pmid=19427502 |doi=10.1016/j.mcna.2009.02.010 |url=http://journals.elsevierhealth.com/retrieve/pii/S0025-7125(09)00025-X|access-date=2009-06-20|url-access=subscription }}</ref> [[coronary artery disease]],<ref name="pmid19363848">{{cite journal | vauthors = Agabiti-Rosei E | title = From macro- to microcirculation: benefits in hypertension and diabetes | journal = J Hypertens Suppl | volume = 26 | issue = 3 | pages = S15–9 | date = September 2008 | pmid = 19363848 | doi = 10.1097/01.hjh.0000334602.71005.52}}</ref><ref name="pmid19427499">{{cite journal |vauthors=Murphy BP, Stanton T, Dunn FG |title=Hypertension and myocardial ischemia |journal=[[The Medical Clinics of North America]] |volume=93 |issue=3 |pages=681–95 |date=May 2009 |pmid=19427499 |doi=10.1016/j.mcna.2009.02.003 |url=http://journals.elsevierhealth.com/retrieve/pii/S0025-7125(09)00018-2|access-date=2009-06-20|url-access=subscription }}</ref> [[stroke]],<ref name="pmid19393824"/> [[renal disease]],<ref name="pmid12728683">{{cite journal |vauthors=Tylicki L, Rutkowski B |title=[Hypertensive nephropathy: pathogenesis, diagnosis and treatment] |language=pl |journal=[[Polski Merkuriusz Lekarski]] |volume=14 |issue=80 |pages=168–73 |date=February 2003 |pmid=12728683 }}</ref><ref name="pmid19195963">{{cite journal |vauthors=Truong LD, Shen SS, Park MH, Krishnan B |title=Diagnosing nonneoplastic lesions in nephrectomy specimens |journal=[[Archives of Pathology & Laboratory Medicine]] |volume=133 |issue=2 |pages=189–200 |date=February 2009 |pmid=19195963 |doi= 10.5858/133.2.189|url=https://www.archivesofpathology.org/doi/full/10.1043/1543-2165-133.2.189|access-date=2009-06-20|url-access=subscription }}</ref><ref name="pmid11842376">{{cite journal |vauthors=Tracy RE, White S |title=A method for quantifying adrenocortical nodular hyperplasia at autopsy: some use of the method in illuminating hypertension and atherosclerosis |journal=[[Annals of Diagnostic Pathology]] |volume=6 |issue=1 |pages=20–9 |date=February 2002 |pmid=11842376 |doi= 10.1053/adpa.2002.30606}}</ref> and [[peripheral arterial disease]].<ref name="pmid18672184">{{cite journal |author=Aronow WS |title=Hypertension and the older diabetic |journal=[[Clinics in Geriatric Medicine]] |volume=24 |issue=3 |pages=489–501, vi–vii |date=August 2008 |pmid=18672184 |doi=10.1016/j.cger.2008.03.001 |url=http://journals.elsevierhealth.com/retrieve/pii/S0749-0690(08)00012-8|access-date=2009-06-20|url-access=subscription }}</ref><ref name="pmid19008688">{{cite journal |vauthors=Gardner AW, Afaq A |journal=[[Journal of Cardiopulmonary Rehabilitation and Prevention]] |volume=28 |issue=6 |pages=349–57 |year=2008 |pmid=19008688 |doi=10.1097/HCR.0b013e31818c3b96 |pmc=2743684|title=Management of Lower Extremity Peripheral Arterial Disease }}</ref> It is the most important [[Risk factor (epidemiology)|risk factor]] for [[cardiovascular]] [[morbidity]] and [[mortality rate|mortality]], in [[industrialized countries]].<ref name="pmid19149532">{{cite journal |vauthors=Novo S, Lunetta M, Evola S, Novo G |title=Role of ARBs in the blood hypertension therapy and prevention of cardiovascular events |journal=[[Current Drug Targets]] |volume=10 |issue=1 |pages=20–5 |date=January 2009 |pmid=19149532 |doi=10.2174/138945009787122897 |url=http://www.bentham-direct.org/pages/content.php?CDT/2009/00000010/00000001/0003J.SGM |access-date=2009-06-20 |archive-url=https://archive.today/20130112095900/http://www.bentham-direct.org/pages/content.php?CDT/2009/00000010/00000001/0003J.SGM |archive-date=2013-01-12 |url-status=usurped |url-access=subscription }}</ref>

=== Congenital heart defects ===
{{Main|Congenital heart defect}}

A congenital heart defect, also known as a "congenital heart anomaly" or "congenital heart disease", is a problem in the structure of the heart that is present at [[childbirth|birth]].<ref name=NIH2011>{{cite web|title=What Are Congenital Heart Defects?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/chd|website=National Heart, Lung, and Blood Institute|access-date=10 August 2015|date=July 1, 2011}}</ref> Signs and symptoms depend on the specific type of problem.<ref name=WHO2011/> Symptoms can vary from none to life-threatening.<ref name=NIH2011/> When present they may include rapid breathing, [[cyanosis|bluish skin]], poor weight gain, and feeling tired.<ref name=NIH2011Sym-b/> It does not cause chest pain.<ref name=NIH2011Sym-b>{{cite web|title=What Are the Signs and Symptoms of Congenital Heart Defects?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/chd/signs|website=National Heart, Lung, and Blood Institute|access-date=10 August 2015|date=July 1, 2011}}</ref> Most congenital heart problems do not occur with other diseases.<ref name=WHO2011>{{cite book|author1=Shanthi Mendis|author2=Pekka Puska|author3=Bo Norrving|author4=World Health Organization|title=Global Atlas on Cardiovascular Disease Prevention and Control|url=http://whqlibdoc.who.int/publications/2011/9789241564373_eng.pdf?ua=1|year=2011|publisher=World Health Organization in collaboration with the World Heart Federation and the World Stroke Organization|pages=3, 60|isbn=978-92-4-156437-3}}</ref> Complications that can result from heart defects include [[heart failure]].<ref name=NIH2011Sym-b/>

<!-- Cause and diagnosis-->
The cause of a congenital heart defect is often unknown.<ref>{{cite web|title=What Causes Congenital Heart Defects?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/chd/causes|website=National Heart, Lung, and Blood Institute|access-date=10 August 2015|date=July 1, 2011}}</ref> Certain cases may be due to infections during [[pregnancy]] such as [[rubella]], use of certain medications or drugs such as [[ethanol|alcohol]] or [[tobacco]], parents being closely related, or poor nutritional status or [[obesity]] in the mother.<ref name=WHO2011/><ref name=Dean2014>{{cite journal|last1=Dean|first1=SV|last2=Lassi|first2=ZS|last3=Imam|first3=AM|last4=Bhutta|first4=ZA|title=Preconception care: nutritional risks and interventions|journal=Reproductive Health|date=26 September 2014|volume=11|issue=Suppl 3 |pages=S3|pmid=25415364|doi=10.1186/1742-4755-11-s3-s3|pmc=4196560 |doi-access=free }}</ref> Having a parent with a congenital heart defect is also a risk factor.<ref name=Mil2011/> A number of genetic conditions are associated with heart defects including [[Down syndrome]], [[Turner syndrome]], and [[Marfan syndrome]].<ref name=WHO2011/> Congenital heart defects are divided into two main groups: [[cyanotic heart defect]]s and [[non-cyanotic heart defect]]s, depending on whether the child has the potential to turn bluish in color.<ref name=WHO2011/> The problems may involve the interior walls of the heart, the [[heart valves]], or the large blood vessels that lead to and from the heart.<ref name=NIH2011/>

<!-- Prevention and treatment -->
Congenital heart defects are partly preventable through [[rubella vaccination]], the adding of [[iodine]] to salt, and the adding of [[folic acid]] to certain food products.<ref name=WHO2011/> Some defects do not need treatment.<ref name=NIH2011/> Other may be effectively treated with [[catheter procedure|catheter based procedures]] or [[cardiac surgery|heart surgery]].<ref name=NIH2011Tx/> Occasionally a number of operations may be needed.<ref name=NIH2011Tx>{{cite web|title=How Are Congenital Heart Defects Treated?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/chd/treatment|website=National Heart, Lung, and Blood Institute|access-date=10 August 2015|date=July 1, 2011}}</ref> Occasionally [[heart transplantation]] is required.<ref name=NIH2011Tx/> With appropriate treatment outcomes, even with complex problems, are generally good.<ref name=NIH2011/>

<!-- Epidemiology and prognosis -->
Heart defects are the most common [[birth defect]].<ref name=WHO2011/><ref name=GBD2015/> In 2013 they were present in 34.3 million people globally.<ref name="GBD2015">{{cite journal |last1= Vos|first1= Theo|last2= Barber|first2= Ryan M.|last3= Bell|first3= Brad|last4= Bertozzi-Villa|first4= Amelia|last5= Biryukov|first5= Stan|last6= Bolliger|first6= Ian|last7= Charlson|first7= Fiona|last8= Davis|first8= Adrian|last9= Degenhardt|first9= Louisa|last10= Dicker|first10= Daniel|last11= Duan|first11= Leilei|last12= Erskine|first12= Holly|last13= Feigin|first13= Valery L.|last14= Ferrari|first14= Alize J.|last15= Fitzmaurice|first15= Christina|last16= Fleming|first16= Thomas|last17= Graetz|first17= Nicholas|last18= Guinovart|first18= Caterina|last19= Haagsma|first19= Juanita|last20= Hansen|first20= Gillian M.|last21= Hanson|first21= Sarah Wulf|last22= Heuton|first22= Kyle R.|last23= Higashi|first23= Hideki|last24= Kassebaum|first24= Nicholas|last25= Kyu|first25= Hmwe|last26= Laurie|first26= Evan|last27= Liang|first27= Xiofeng|last28= Lofgren|first28= Katherine|last29= Lozano|first29= Rafael|last30= MacIntyre|first30= Michael F.|display-authors= 1|date=7 June 2015 |title=Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013 |journal=Lancet |volume=386 |issue=9995 |pages=743–800 |doi=10.1016/S0140-6736(15)60692-4 |pmc=4561509 |pmid=26063472}}</ref> They affect between 4 and 75 per 1,000 live births depending upon how they are diagnosed.<ref name=WHO2011/><ref name=Mil2011>{{cite book|last1=Milunsky|first1=Aubrey|title=Genetic Disorders and the Fetus: Diagnosis, Prevention and Treatment|date=2011|publisher=John Wiley & Sons|isbn=9781444358216|chapter-url=https://books.google.com/books?id=yY-gIvbnRDUC&pg=PT28|chapter=1}}</ref> About 6 to 19 per 1,000 cause a moderate to severe degree of problems.<ref name=Mil2011/> Congenital heart defects are the leading cause of birth defect-related deaths.<ref name=WHO2011/> In 2013 they resulted in 323,000 deaths down from 366,000 deaths in 1990.<ref name="pmid25530442"/>

==== Tetralogy of Fallot ====
[[Tetralogy of Fallot]] is the most common congenital heart disease arising in 1–3 cases per 1,000 births. The cause of this defect is a [[ventricular septal defect]] (VSD) and an [[overriding aorta]]. These two defects combined causes deoxygenated blood to bypass the lungs and going right back into the circulatory system. The [[modified Blalock-Taussig shunt]] is usually used to fix the circulation. This procedure is done by placing a graft between the subclavian artery and the ipsilateral pulmonary artery to restore the correct blood flow.

==== Pulmonary atresia ====
[[Pulmonary atresia]] happens in 7–8 per 100,000 births and is characterized by the aorta branching out of the right ventricle. This causes the deoxygenated blood to bypass the lungs and enter the circulatory system. Surgeries can fix this by redirecting the aorta and fixing the right ventricle and pulmonary artery connection.

There are two types of pulmonary atresia, classified by whether or not the baby also has a [[ventricular septal defect]].<ref name="Medscape2015">{{cite web |url=https://emedicine.medscape.com/article/892980-overview |title=Ventricular Septal Defects: Background, Anatomy, Pathophysiology |vauthors = Ramaswamy P, Webber HS|website=Medscape |publisher=WebMD LLC |access-date=August 22, 2017 }}</ref><ref name=":0">{{cite web |url=https://www.cdc.gov/ncbddd/heartdefects/pulmonaryatresia.html |title=Facts about Pulmonary Atresia: Types of Pulmonary Atresia|author=<!--Not stated--> |website=CDC |publisher=USA.gov |access-date=August 22, 2017 }}</ref>
* Pulmonary atresia with an intact ventricular septum: This type of pulmonary atresia is associated with complete and intact [[septum]] between the ventricles.<ref name=":0" />
* Pulmonary atresia with a ventricular septal defect: This type of pulmonary atresia happens when a ventricular septal defect allows blood to flow into and out of the right ventricle.<ref name=":0" />

==== Double outlet right ventricle ====
[[Double outlet right ventricle]] (DORV) is when both great arteries, the pulmonary artery and the aorta, are connected to the right ventricle. There is usually a VSD in different particular places depending on the variations of DORV, typically 50% are subaortic and 30%. The surgeries that can be done to fix this defect can vary due to the different physiology and blood flow in the defected heart. One way it can be cured is by a VSD closure and placing conduits to restart the blood flow between the left ventricle and the aorta and between the right ventricle and the pulmonary artery. Another way is systemic-to-pulmonary artery shunt in cases associated with [[Pulmonic stenosis|pulmonary stenosis]]. Also, a [[Atrial septostomy|balloon atrial septostomy]] can be done to relieve hypoxemia caused by DORV with the Taussig-Bing anomaly while surgical correction is awaited.<ref>{{Cite journal |last=Rao |first=P. Syamasundar |date=2019-04-04 |title=Management of Congenital Heart Disease: State of the Art—Part II—Cyanotic Heart Defects |journal=Children |volume=6 |issue=4 |pages=54 |doi=10.3390/children6040054 |issn=2227-9067 |pmc=6518252 |pmid=30987364|doi-access=free }}</ref>

==== Transposition of great arteries ====
[[File:D-tga-575px.jpg|thumb|Dextro-transposition of the Great Arteries]]
There are two different types of [[Transposition of the great vessels|transposition of the great arteries]], [[Dextro-Transposition of the great arteries|Dextro-transposition of the great arteries]] and [[Levo-Transposition of the great arteries|Levo-transposition of the great arteries]], depending on where the chambers and vessels connect. Dextro-transposition happens in about 1 in 4,000 newborns and is when the right ventricle pumps blood into the aorta and deoxygenated blood enters the bloodstream. The temporary procedure is to create an [[atrial septal defect]]. A permanent fix is more complicated and involves redirecting the pulmonary return to the right atrium and the systemic return to the left atrium, which is known as the [[Senning procedure]]. The [[Rastelli procedure]] can also be done by rerouting the left ventricular outflow, dividing the pulmonary trunk, and placing a conduit in between the right ventricle and pulmonary trunk. Levo-transposition happens in about 1 in 13,000 newborns and is characterized by the left ventricle pumping blood into the lungs and the right ventricle pumping the blood into the aorta. This may not produce problems at the beginning, but will eventually due to the different pressures each ventricle uses to pump blood. Switching the left ventricle to be the systemic ventricle and the right ventricle to pump blood into the pulmonary artery can repair levo-transposition.{{citation needed|date=April 2021}}

==== Persistent truncus arteriosus ====
[[Persistent truncus arteriosus]] is when the [[truncus arteriosus]] fails to split into the aorta and pulmonary trunk. This occurs in about 1 in 11,000 live births and allows both oxygenated and deoxygenated blood into the body. The repair consists of a VSD closure and the Rastelli procedure.<ref>{{Cite web |title=Persistent Truncus Arteriosus – Pediatrics |url=https://www.msdmanuals.com/professional/pediatrics/congenital-cardiovascular-anomalies/persistent-truncus-arteriosus |access-date=2022-06-19 |website=MSD Manual Professional Edition |language=en}}</ref><ref>{{Cite web |last=Cleveland Clinic |date=September 17, 2021 |title=Truncus Arteriosus |url=https://my.clevelandclinic.org/health/diseases/14785-truncus-arteriosus |url-status=live |website=[[Cleveland Clinic]]|archive-url=https://web.archive.org/web/20200804222430/https://my.clevelandclinic.org/health/diseases/14785-truncus-arteriosus |archive-date=2020-08-04 }}</ref>

==== Ebstein anomaly ====
[[Ebstein's anomaly]] is characterized by a right atrium that is significantly enlarged and a heart that is shaped like a box. This is very rare and happens in less than 1% of congenital heart disease cases. The surgical repair varies depending on the severity of the disease.<ref>{{Cite journal|last=Bhat|first=Venkatraman|title=Illustrated Imaging Essay on Congenital Heart Diseases: Multimodality Approach Part III: Cyanotic Heart Diseases and Complex Congenital Anomalies|journal=Journal of Clinical and Diagnostic Research|doi=10.7860/jcdr/2016/21443.8210|pmc=5020285|pmid=27630924|volume=10|issue=7|year=2016|pages=TE01–10}}</ref>

Pediatric cardiology is a sub-specialty of [[pediatrics]]. To become a pediatric cardiologist in the U.S., one must complete a three-year residency in pediatrics, followed by a three-year fellowship in pediatric cardiology. Per [[doximity]], pediatric cardiologists make an average of $303,917 in the U.S.<ref name="r1" />

== Diagnostic tests in cardiology ==
{{Main|Diagnostic tests in cardiology}}

[[Diagnostic tests in cardiology]] are the methods of identifying heart conditions associated with healthy vs. unhealthy, [[pathology|pathologic]] heart function. The starting point is obtaining a [[medical history]], followed by [[Auscultation]]. Then [[blood test]]s, [[Cardiology diagnostic tests and procedures#Electrophysiology|electrophysiological procedures]], and [[cardiac imaging]] can be ordered for further analysis. Electrophysiological procedures include electrocardiogram, [[cardiac monitoring]], [[cardiac stress test]]ing, and the [[electrophysiology study]].{{citation needed|date=April 2021}}

== Trials ==
Cardiology is known for [[randomized controlled trial]]s that guide clinical treatment of cardiac diseases. While dozens are published every year, there are landmark trials that shift treatment significantly. Trials often have an acronym of the trial name, and this acronym is used to reference the trial and its results. Some of these landmark trials include:

* V-HeFT (1986) — use of vasodilators (hydralazine and isosorbide dinitrate) in heart failure
* ISIS-2 (1988) — use of aspirin in myocardial infarction
* CASE I (1991) — use of [[antiarrhythmic agent]]s after a heart attack increases mortality
* SOLVD (1991) — use of [[ACE inhibitor]]s in heart failure
* 4S (1994) — [[statin]]s reduce risk of heart disease
* CURE (1991) — use of [[dual antiplatelet therapy]] in [[NSTEMI]]
* MIRACLE (2002) — use of [[cardiac resynchronization therapy]] in heart failure
* SCD-HeFT (2005) — the use of [[implantable cardioverter-defibrillator]] in heart failure
* RELY (2009), ROCKET-AF (2011), ARISTOTLE (2011) — use of [[DOAC]]s in [[atrial fibrillation]] instead of warfarin
* PARADIGM-HF (2014) — use of angiotensin-neprilysin inhibitor in heart failure
* ISCHEMIA (2020) — medical therapy is as good as [[coronary stent]]s in stable heart disease
* EMPEROR-Preserved (2021) — SGLT2 receptors in heart failure

== Cardiology community ==
=== Associations ===
* [[American College of Cardiology]]
* [[American Heart Association]]
* [[European Society of Cardiology]]
* [[Heart Rhythm Society]]
* [[Canadian Cardiovascular Society]]
* [[Indian Heart Association]]
* [[National Heart Foundation of Australia]]
* Cardiology Society of India

=== Journals ===
{{main category|Cardiology journals}}
* [[Acta Cardiologica]]
* [[American Journal of Cardiology]]
* [[Annals of Cardiac Anaesthesia]]
* [[Current Research: Cardiology]]
* [[Cardiology in Review]]
* [[Circulation (journal)|Circulation]]
* [[Circulation Research]]
* [[Clinical and Experimental Hypertension]]
* [[Clinical Cardiology]]
* [[EP – Europace]]
* [[European Heart Journal]]
* [[Heart (journal)|Heart]]
* [[Heart Rhythm]]
* [[International Journal of Cardiology]]
* [[Journal of the American College of Cardiology]]
* [[Pacing and Clinical Electrophysiology]]
* Indian Heart Journal

=== Cardiologists ===
{{Main|List of cardiologists}}
* [[Robert Atkins (nutritionist)|Robert Atkins]] (1930–2003), known for the [[Atkins diet]]
* [[Christiaan Barnard]] (1922–2001), cardiac surgeon who performed the world's first human-to-human heart transplant operation
* [[Eugene Braunwald]] (born 1929), editor of ''Braunwald's Heart Disease'' and 1000+ publications
* [[Wallace Brigden]] (1916–2008), identified [[cardiomyopathy]]
* [[Manoj Durairaj]] (1971– ), cardiologist from Pune, India who received [[Pro Ecclesia et Pontifice]]
* [[Willem Einthoven]] (1860–1927), a physiologist who built the first practical ECG and won the 1924 [[Nobel Prize in Physiology or Medicine]] ("for the discovery of the mechanism of the electrocardiogram")
* [[Werner Forssmann]] (1904–1979), who infamously performed the first human catheterization on himself that led to him being let go from [[Berliner Charité Hospital]], quitting cardiology as a speciality, and then winning the 1956 [[Nobel Prize in Physiology or Medicine]]  ("for their discoveries concerning heart catheterization and pathological changes in the circulatory system")
* [[Andreas Gruentzig]] (1939–1985), first developed balloon angioplasty
* [[William Harvey]] (1578–1657), wrote ''[[Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus]]'' that first described the closed circulatory system and whom Forssmann described as founding cardiology in his Nobel lecture
* [[Murray S. Hoffman]] (1924–2018) As president of the Colorado Heart Association, he initiated one of the first jogging programs promoting cardiac health
* [[Max Holzmann]] (1899–1994), co-founder of the Swiss Society of Cardiology, president from 1952 to 1955
* [[Samuel A. Levine]] (1891–1966), recognized the sign known as [[Levine's sign]] as well as the current grading of the intensity of [[heart murmurs]], known as the [[Levine scale]]
* Henry Joseph Llewellyn "Barney" Marriott (1917–2007), ECG interpretation and ''Practical Electrocardiography''<ref>{{cite journal|last1=Upshaw|first1=Charles|title=Henry J. L. Marriott: Lucid Teacher of Electrocardiography|journal=Clinical Cardiology|date=18 April 2007|volume=30|issue=4|pages=207–8|doi=10.1002/clc.6|pmid=17443652|pmc=6652921}}</ref>
* [[Bernard Lown]] (1921–2021), original developer of the defibrillator
* [[Woldemar Mobitz]] (1889–1951), described and classified the two types of [[second-degree atrioventricular block]] often called "Mobitz Type I" and "Mobitz Type II"
* [[Jacqueline Noonan]] (1928–2020), discoverer of [[Noonan syndrome]] that is the top syndromic cause of congenital heart disease
* [[John Parkinson (physician)|John Parkinson]] (1885–1976), known for [[Wolff–Parkinson–White syndrome]]
* [[Helen B. Taussig]] (1898–1986), founder of pediatric cardiology and extensively worked on [[blue baby syndrome]]
* [[Paul Dudley White]] (1886–1973), known for [[Wolff–Parkinson–White syndrome]]
* [[Fredrick Arthur Willius]] (1888–1972), founder of the cardiology department at the [[Mayo Clinic]] and an early pioneer of [[electrocardiography]]
* [[Louis Wolff]] (1898–1972), known for [[Wolff–Parkinson–White syndrome]]
* [[Karel Frederik Wenckebach]] (1864–1940), first described what is now called type I [[second-degree atrioventricular block]] in 1898

==See also==
{{Portal|medicine}}
* [[Glossary of medicine]]
* [[List of cardiac pharmaceutical agents]]
* [[List of cardiovascular clinical trials]]
* [[Outline of cardiology]]
{{Clear}}

== References ==
{{Reflist}}

== Sources ==
* {{cite book |editor-last=Braunwald |editor-first=Eugene |editor-link=Eugene Braunwald |date=2019 |title= Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine|url= |location= |publisher=Elsevier |page= |isbn= 978-0-323-46299-0}}
* {{cite book |editor-last1=Ramrakha |editor-first1=Punit |editor-first2=Jonathan|editor-last2=Hill|date=2012|edition=2nd |title= Oxford Handbook of Cardiology|publisher=Oxford University Press |isbn= 978-0-19-964321-9}}

==External links==
{{wiktionary}}
* [https://www.heart.org/ American Heart Association]

{{Medicine}}
{{Cardiovascular system}}
{{Cardiovascular system symptoms and signs}}
{{Heart diseases}}
{{Cardiac procedures}}

{{Authority control}}

[[Category:Cardiology| ]]