cardiology cardiology cardiology (from ancient greek καρδίᾱ (kardiā) 'heart', and -λογία (-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 defects, coronary artery disease, heart failure, valvular heart disease and electrophysiology. physicians who specialize in this field of medicine are called cardiologists, a speciality of internal medicine. pediatric cardiologists are pediatricians who specialize in cardiology. physicians who specialize in cardiac surgery are called cardiothoracic surgeons or cardiac surgeons, a speciality of general surgery. cardiologyblood flow diagram of the human heart. blue components indicate de-oxygenated blood pathways and red components indicate oxygenated blood pathways.systemcardiovascularsubdivisionsinterventional cardiology, clinical cardiac electrophysiology, heart failure and transplant cardiology, nuclear cardiology, adult congenital heart disease, pediatric cardiology, echocardiography, cardiovascular imagingsignificant diseasesheart disease, cardiovascular disease, atherosclerosis, cardiomyopathy, hypertension (high blood pressure)significant testsblood tests, electrophysiology study, cardiac imaging, ecg, echocardiograms, stress testspecialistcardiologistglossaryglossary of medicine cardiologistoccupationnames physician surgeon occupation typespecialtyactivity sectorsmedicine, surgerydescriptioneducation required 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) fields ofemploymenthospitals, clinics 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 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 minimally invasive procedures such as cardiac catheterization and pacemaker implantation are performed by cardiologists who have additional training in non-surgical interventions (interventional cardiology and electrophysiology respectively). adult cardiology cardiology is a specialty of internal medicine. to be 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./diplomate of national board (dnb) in cardiology. per doximity, adult cardiologists earn an average of $436,849 per year in the u.s. cardiac electrophysiology main article: 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) catheter recording of spontaneous activity as well as of cardiac responses to programmed electrical stimulation (pes). these studies are performed to assess complex arrhythmias, 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 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. clinical cardiac electrophysiology main article: 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 8 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. cardiogeriatrics main article: 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. imaging further information: echocardiography, cardiac magnetic resonance imaging, and 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. interventional cardiology main article: 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 cannulating the heart under 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 specialization of general cardiology to just that of the 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. cardiooncology main article: 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 whom have experienced cardiac complications of chemotherapy. preventive cardiology and cardiac rehabilitation further information: 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. pediatric cardiology tetralogy of fallot helen b. taussig is known as the founder of pediatric cardiology. she became famous through her work with tetralogy congenital heart defect in which 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. tetralogy of fallot, pulmonary atresia, double outlet right ventricle, 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 & 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 blood flow through the valves main article: heart as the center focus of cardiology, the heart has numerous anatomical features (e.g., atria, ventricles, heart valves) and numerous physiological features (e.g., systole, heart sounds, afterload) that have been encyclopedically documented for many centuries. 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 lungs — 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 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 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 potentials generated in the pacemaker propagate throughout the heart in a specific pattern. the system that carries this potential is called the electrical conduction system. 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 fluidic movement of blood and the functionality of the heart as a pump. the mechanical part