The following outline is provided as an overview of and topical guide to cardiology, the branch of medicine dealing with disorders of the human heart. [1] 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 cardiology are called cardiologists.
Cardiology can be described as all of the following:
Heart –
The cardiac physical exam focuses on portions of the physical exam that elucidate information about diseases and disorders outlined below. Clinical judgment, of course, should guide the physical exam but the following are pertinent things related to a general / broad cardiac exam.
Coronary artery disease is not currently reversible and eventually requires surgical management if it progresses.
Various cardiology diagnostic tests and procedures.
There are several classes of pharmaceutical drugs used in cardiology to manage various diseases and many of them have cardiovascular side effects.
Drugs that manipulate the cardiovascular system do so through several ways. The first is ion channels, which are often manipulated to manage arrhythmias. The second is receptors of various types. The third is manipulation of enzymes.
Ion channels are responsible for cell membrane voltage, depolarization, and repolarization. These actions lead to conduction of signals down nerves and contraction of cardiomyocytes. Perhaps the most prominent manipulation of ion channels is through antiarrhythmic agents. These agents are commonly classified by the type of ion they manipulate and named the Vaughan Williams classification:
Specifically, types I, III, & IV manipulate ion channels while the others are not.
The adrenergic receptor is a set of receptors that are commonly manipulated. Four properties of the heart — chronotropy, dromotropy, inotropy, & lusitropy — are manipulated by adrenergic receptors. For example, the β1 receptor increases all four of these properties: chronotropy at the SA node, dromotropy through the AV node, inotropy of the cardiomyocytes through increased calcium, and lusitropy through phosphorylation of phospholamban. Catecholamines are a set of drugs and hormones that manipulate the adrenergic receptors. The natural catecholamines are norepinephrine, epinephrine, and dopamine. There are numerous other drugs (e.g., dobutamine, ephedrine, isoproterenol) that manipulate the adrenergic receptors and have variable specificity for the receptors and are, thus, used for various reasons.
Angiotensin II receptor antagonists (ARBs) block the angiotensin II receptors that are linked to hypertension and heart failure, mainly through vasodilation & heart remodeling inhibition.
ACE inhibitors works upstream from angiotensin II receptor antagonists and have similar effects on management of hypertension and heart failure.
Sodium nitroprusside and nitroglycerin function by causing vasodilation through nitric oxide, which manipulates cGMP levels through guanylate cyclase.
COX inhibitors (namely aspirin), warfarin, direct Xa inhibitors, direct thrombin inhibitors, heparin, low-molecular weight heparins, antibodies (e.g., abciximab), and a few others are used for anticoagulation therapy. This is important in those predisposed to blood clots (e.g., Factor V Leiden) but also for thrombus formation when an atherosclerotic plaque rupture that would, otherwise, lead to myocardial infarction.
Numerous drug classes have well-known cardiovascular side effects.
Cardiology 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 specialty 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 specialty of general surgery.
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest, called the mediastinum.
Coronary circulation is the circulation of blood in the arteries and veins that supply the heart muscle (myocardium). Coronary arteries supply oxygenated blood to the heart muscle. Cardiac veins then drain away the blood after it has been deoxygenated. Because the rest of the body, and most especially the brain, needs a steady supply of oxygenated blood that is free of all but the slightest interruptions, the heart is required to function continuously. Therefore its circulation is of major importance not only to its own tissues but to the entire body and even the level of consciousness of the brain from moment to moment. Interruptions of coronary circulation quickly cause heart attacks, in which the heart muscle is damaged by oxygen starvation. Such interruptions are usually caused by coronary ischemia linked to coronary artery disease, and sometimes to embolism from other causes like obstruction in blood flow through vessels.
Aortic stenosis is the narrowing of the exit of the left ventricle of the heart, such that problems result. It may occur at the aortic valve as well as above and below this level. It typically gets worse over time. Symptoms often come on gradually with a decreased ability to exercise often occurring first. If heart failure, loss of consciousness, or heart related chest pain occur due to AS the outcomes are worse. Loss of consciousness typically occurs with standing or exercising. Signs of heart failure include shortness of breath especially when lying down, at night, or with exercise, and swelling of the legs. Thickening of the valve without narrowing is known as aortic sclerosis.
A heart valve is a biological one-way valve that allows blood to flow in one direction through the chambers of the heart. Four valves are usually present in a mammalian heart and together they determine the pathway of blood flow through the heart. A heart valve opens or closes according to differential blood pressure on each side.
Heart sounds are the noises generated by the beating heart and the resultant flow of blood through it. Specifically, the sounds reflect the turbulence created when the heart valves snap shut. In cardiac auscultation, an examiner may use a stethoscope to listen for these unique and distinct sounds that provide important auditory data regarding the condition of the heart.
Heart murmurs are unique heart sounds produced when blood flows across a heart valve or blood vessel. This occurs when turbulent blood flow creates a sound loud enough to hear with a stethoscope. Turbulent blood flow is not smooth. The sound differs from normal heart sounds by their characteristics. For example, heart murmurs may have a distinct pitch, duration and timing. The major way health care providers examine the heart on physical exam is heart auscultation; another clinical technique is palpation, which can detect by touch when such turbulence causes the vibrations called cardiac thrill. A murmur is a sign found during the cardiac exam. Murmurs are of various types and are important in the detection of cardiac and valvular pathologies.
Systole is the part of the cardiac cycle during which some chambers of the heart contract after refilling with blood.
A ventricle is one of two large chambers located toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the upper heart that is smaller than a ventricle. Interventricular means between the ventricles, while intraventricular means within one ventricle.
Afterload is the pressure that the heart must work against to eject blood during systole. Afterload is proportional to the average arterial pressure. As aortic and pulmonary pressures increase, the afterload increases on the left and right ventricles respectively. Afterload changes to adapt to the continually changing demands on an animal's cardiovascular system. Afterload is proportional to mean systolic blood pressure and is measured in millimeters of mercury.
Mitral stenosis is a valvular heart disease characterized by the narrowing of the opening of the mitral valve of the heart. It is almost always caused by rheumatic valvular heart disease. Normally, the mitral valve is about 5 cm2 during diastole. Any decrease in area below 2 cm2 causes mitral stenosis. Early diagnosis of mitral stenosis in pregnancy is very important as the heart cannot tolerate increased cardiac output demand as in the case of exercise and pregnancy. Atrial fibrillation is a common complication of resulting left atrial enlargement, which can lead to systemic thromboembolic complications such as stroke.
Mitral regurgitation(MR), also known as mitral insufficiency or mitral incompetence, is a form of valvular heart disease in which the mitral valve is insufficient and does not close properly when the heart pumps out blood. It is the abnormal leaking of blood backwards – regurgitation from the left ventricle, through the mitral valve, into the left atrium, when the left ventricle contracts. Mitral regurgitation is the most common form of valvular heart disease.
A transthoracic echocardiogram (TTE) is the most common type of echocardiogram, which is a still or moving image of the internal parts of the heart using ultrasound. In this case, the probe is placed on the chest or abdomen of the subject to get various views of the heart. It is used as a non-invasive assessment of the overall health of the heart, including a patient's heart valves and degree of heart muscle contraction. The images are displayed on a monitor for real-time viewing and then recorded.
Valvular heart disease is any cardiovascular disease process involving one or more of the four valves of the heart. These conditions occur largely as a consequence of aging, but may also be the result of congenital (inborn) abnormalities or specific disease or physiologic processes including rheumatic heart disease and pregnancy.
A plot of a system's pressure versus volume has long been used to measure the work done by the system and its efficiency. This analysis can be applied to heat engines and pumps, including the heart. A considerable amount of information on cardiac performance can be determined from the pressure vs. volume plot. A number of methods have been determined for measuring PV-loop values experimentally.
A ventricular outflow tract obstruction is a heart condition in which either the right or left ventricular outflow tract is blocked or obstructed. These obstructions represent a spectrum of disorders. Majority of these cases are congenital, but some are acquired throughout life.