Cardiology: Difference between revisions

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{{short description|Branch of medicine dealing with the heart}}

{{Infobox medical speciality

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'''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 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]].

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. However, some invasive procedures such as [[cardiac catheterization]] and [[Artificial cardiac pacemaker#Insertion|pacemaker implantation]] are performed by cardiologists.

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 [[cardiac electrophysiology]], [[echocardiography]], [[interventional cardiology]], and [[nuclear cardiology]]. Recognized subspecialties in the U.S. by the [[American Osteopathic Association Bureau of Osteopathic Specialists]] include [[clinical cardiac electrophysiology]] and [[interventional cardiology]].

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.

Per [[Doximity]], adult cardiologists earn an average of $436,849 per year in the U.S.

{{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).

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.

{{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.

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.

{{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. Vascular disorders such as [[atherosclerosis]] and [[peripheral arterial disease]] cause significant morbidity and mortality in aged people.

{{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.

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.

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.

{{Main|Interventional cardiology}}

Interventional cardiology is a branch of cardiology that deals specifically with the [[catheter]] based treatment of structural heart diseases. 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.

A relatively newer specialization of cardiology is in the field of heart failure and heart transplant. Specialization of general cardiology to just that of the [[cardiomyopathy|cardiomyopathies]] leads to also specializing in [[heart transplant]] and [[pulmonary hypertension]]. Cardiomyopathy is a heart disease of the heart muscle, where the heart muscle becomes inflamed and thick.  

{{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.

{{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. 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.

[[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]].

[[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.

As more children with congenital heart disease are surviving into adulthood, a hybrid of adult & 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.

[[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.

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]]. 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).

Dysfunction of the electrical system manifests in many ways and may include [[Wolff–Parkinson–White syndrome]], [[ventricular fibrillation]], and [[heart block]].

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.

{{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.

{{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]].

Like all medical examinations, the cardiac examination follows the standard structure of inspection, palpation and auscultation.

{{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.

{{Main|Coronary artery disease}}

Coronary artery disease, also known as "ischemic heart disease", is a group of diseases that includes: [[stable angina]], [[unstable angina]], myocardial infarction, and is one of the causes of [[sudden cardiac death]]. It is within the group of cardiovascular diseases of which it is the most common type. A common symptom is [[chest pain]] or discomfort which may travel into the shoulder, arm, back, neck, or jaw. 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. [[Shortness of breath]] may also occur and sometimes no symptoms are present. The first sign is occasionally a heart attack. Other complications include [[heart failure]] or an [[Heart arrhythmia|irregular heartbeat]].

<!--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. Other risks include [[major depressive disorder|depression]]. 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.

<!-- Prevention and treatment -->

Prevention is by eating a healthy diet, regular exercise, maintaining a healthy weight and not smoking. Sometimes medication for diabetes, high cholesterol, or high blood pressure are also used. There is limited evidence for screening people who are at low risk and do not have symptoms. Treatment involves the same measures as prevention. Additional medications such as [[antiplatelet drug|antiplatelets]] including [[aspirin]], [[beta blocker]]s, or [[Medical use of nitroglycerin|nitroglycerin]] may be recommended. Procedures such as [[percutaneous coronary intervention]] (PCI) or [[coronary artery bypass surgery]] (CABG) may be used in severe disease. 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.

<!--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. The risk of death from CAD for a given age has decreased between 1980 and 2010 especially in [[developed country|developed countries]]. The number of cases of CAD for a given age has also decreased between 1990 and 2010. 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. Rates are higher among men than women of a given age.

{{main|Cardiomyopathy}}

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

{{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. 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]]. Many types of arrhythmia present no symptoms. When symptoms are present, they may include [[palpitations]], or feeling a pause between heartbeats. More serious symptoms may include [[presyncope|lightheadedness]], [[Syncope (medicine)|passing out]], [[shortness of breath]], or [[chest pain]]. While most types of arrhythmia are not serious, some predispose a person to complications such as [[stroke]] or [[heart failure]]. Others may result in [[cardiac arrest]].

<!-- Cause and diagnosis -->

There are four main types of arrhythmia: [[premature heart beat|extra beats]], [[supraventricular tachycardia]]s, [[ventricular arrhythmia]]s, and [[bradyarrhythmia]]s. Extra beats include [[premature atrial contraction]]s, [[premature ventricular contraction]]s, and [[premature junctional contractions]]. Supraventricular tachycardias include [[atrial fibrillation]], [[atrial flutter]], and [[paroxysmal supraventricular tachycardia]].Ventricular arrhythmias include [[ventricular fibrillation]] and [[ventricular tachycardia]]. Arrhythmias are due to problems with the [[electrical conduction system of the heart]]. Arrhythmias may occur in children; however, the normal range for the heart rate is different and depends on age. A number of tests can help diagnose arrhythmia, including an electrocardiogram and [[Holter monitor]].

<!-- Treatment -->

Most arrhythmias can be effectively treated. Treatments may include medications, medical procedures such as a [[pacemaker]], and surgery. 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]]. This later group may have more significant side effects especially if taken for a long period of time. Those with an irregular heartbeat are often treated with [[blood thinner]]s to reduce the risk of complications. Those who have severe symptoms from an arrhythmia may receive urgent treatment with a jolt of electricity in the form of [[cardioversion]] or [[defibrillation]].

<!-- Epidemiology -->

Arrhythmia affects millions of people. In Europe and North America, as of 2014, atrial fibrillation affects about 2% to 3% of the population. Atrial fibrillation and atrial flutter resulted in 112,000 deaths in 2013, up from 29,000 in 1990. [[Sudden cardiac death]] is the cause of about half of deaths due to cardiovascular disease or about 15% of all deaths globally. About 80% of sudden cardiac death is the result of ventricular arrhythmias. Arrhythmias may occur at any age but are more common among older people.

{{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. Symptoms include [[unconsciousness|loss of consciousness]] and [[respiratory arrest|abnormal or absent breathing]]. Some people may have [[chest pain]], [[shortness of breath]], or [[nausea]] before this occurs. If not treated within minutes, [[death]] usually occurs.

<!-- Cause and diagnosis -->

The most common cause of cardiac arrest is [[coronary artery disease]]. Less common causes include [[bleeding|major blood loss]], lack of oxygen, [[hypokalemia|very low potassium]], [[heart failure]], and intense physical exercise. A number of inherited disorders may also increase the risk including [[long QT syndrome]]. The initial heart rhythm is most often [[ventricular fibrillation]]. The diagnosis is confirmed by finding no pulse. While a cardiac arrest may be caused by heart attack or heart failure these are not the same.

<!-- Treatment and prognosis -->

Prevention includes not smoking, physical activity, and maintaining a healthy weight. Treatment for cardiac arrest is immediate [[cardiopulmonary resuscitation]] (CPR) and, if a [[shockable rhythm]] is present, [[defibrillation]]. Among those who survive [[targeted temperature management]] may improve outcomes. An [[implantable cardiac defibrillator]] may be placed to reduce the chance of death from recurrence.

<!-- 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 Cardiac arrest becomes more common with age. It affects males more often than females. The percentage of people who survive with treatment is about 8%. Many who survive have significant [[disability]]. Many U.S. television shows, however, have portrayed unrealistically high survival rates of 67%.

{{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. High blood pressure usually does not cause symptoms. 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]].

<!-- 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. Hypertension can also be caused by other diseases, or occur as a side-effect of drugs.

<!-- Diagnosis -->

Blood pressure is expressed by two measurements, the [[Systole (medicine)|systolic]] and [[diastolic]] pressures, which are the maximum and minimum pressures, respectively. 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. High blood pressure is present if the resting blood pressure is persistently at or above 140/90 mmHg for most adults. Different numbers apply to children. 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.

<!-- Treatment and epidemiology -->

Lifestyle changes and medications can lower blood pressure and decrease the risk of health complications. Lifestyle changes include weight loss, decreased salt intake, physical exercise, and a healthy diet. If changes in lifestyle are insufficient, [[blood pressure medication]]s may be used. A regimen of up to three medications effectively controls blood pressure in 90% of people. 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]]. 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 while others do not. High blood pressure affects between 16% and 37% of the population globally. In 2010, hypertension was believed to have been a factor in 18% (9.4 million) deaths.

{{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, 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.

[[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]].

[[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. Hypertension is a risk factor for all clinical manifestations of [[atherosclerosis]] since it is a risk factor for atherosclerosis itself. It is an independent predisposing factor for [[heart failure]], [[coronary artery disease]], [[stroke]], [[renal disease]], and [[peripheral arterial disease]]. It is the most important [[risk factor]] for [[cardiovascular]] [[morbidity]] and [[mortality rate|mortality]], in [[industrialized countries]].

{{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]]. Signs and symptoms depend on the specific type of problem. Symptoms can vary from none to life-threatening. When present they may include rapid breathing, [[cyanosis|bluish skin]], poor weight gain, and feeling tired. It does not cause chest pain. Most congenital heart problems do not occur with other diseases. Complications that can result from heart defects include [[heart failure]].

<!-- Cause and diagnosis-->

The cause of a congenital heart defect is often unknown. 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. Having a parent with a congenital heart defect is also a risk factor. A number of genetic conditions are associated with heart defects including [[Down syndrome]], [[Turner syndrome]], and [[Marfan syndrome]]. 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. 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.

<!-- 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. Some defects do not need treatment. Other may be effectively treated with [[catheter procedure|catheter based procedures]] or [[cardiac surgery|heart surgery]]. Occasionally a number of operations may be needed. Occasionally [[heart transplantation]] is required. With appropriate treatment outcomes, even with complex problems, are generally good.

<!-- Epidemiology and prognosis -->

Heart defects are the most common [[birth defect]]. In 2013 they were present in 34.3 million people globally. They affect between 4 and 75 per 1,000 live births depending upon how they are diagnosed. About 6 to 19 per 1,000 cause a moderate to severe degree of problems. Congenital heart defects are the leading cause of birth defect-related deaths. In 2013 they resulted in 323,000 deaths down from 366,000 deaths in 1990.

[[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]] 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]].

* Pulmonary atresia with an intact ventricular septum: This type of pulmonary atresia is associated with complete and intact [[septum]] between the ventricles.

* 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.

[[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.

[[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.

[[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.

[[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.

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.

{{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]].

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 & isosorbide dinitrate) in heart failure

* ISIS-2 (1988) — use of aspirin in myocardial infarction

* EMPEROR-Preserved (2021) — SGLT2 receptors in heart failure

=== Associations ===

* [[American College of Cardiology]]

* Cardiology Society of India

{{main category|Cardiology journals}}

* [[Acta Cardiologica]]

* Indian Heart Journal

{{Infobox Occupation

| name= Cardiologist

  }}

{{Main|List of cardiologists}}

* [[Robert Atkins (nutritionist)|Robert Atkins]] (1930–2003), known for the [[Atkins diet]]

* [[Karel Frederik Wenckebach]] (1864–1940), first described what is now called type I [[second-degree atrioventricular block]] in 1898

{{Portal|medicine}}

* [[Glossary of medicine]]

{{Clear}}

* {{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}}

{{wiktionary}}

* [https://www.heart.org/ American Heart Association]

{{Medicine}}

{{Cardiovascular system}}

{{Cardiac procedures}}

{{二次利用|Date=17 February 2024}}

[[Category:Cardiology| ]]

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