| heart beat | A complete cardiac cycle, including spread of the electrical impulse and the consequent mechanical contraction. Synonym: ictus cordis. (05 Mar 2000) |
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| heart biopsy | <investigation, procedure, surgery> A procedure which involves the removal of a small specimen of cardiac muscle tissue for microscopic analysis. This is generally performed at the same time as a cardiac catheterisation or as a very similar, yet separate, procedure. A small piece of heart tissue is taken via a small forceps inserted into the cardiac catheter site (usually threaded through a vein in the neck). This test may reveal the cause of a cardiomyopathy, myocarditis, amyloidosis or a heart transplant rejection. (21 Mar 1998) |
| heart block | <cardiology, physiology> A conduction disturbance that results in the inappropriate delay (or complete inability) of a electrical impulse, generated in the atria, to reach the ventricles (via the atrioventricular node). Clinical types are divided into first (nonserious), second and third degree (most serious) AV blocks. Some drugs may precipitate an AV block (for example clonidine, methyldopa, verapamil). A permanent pacemaker may be required for a third degree (complete) heart block. (07 Apr 1998) |
| heart bypass, left | Diversion of the flow of blood from the pulmonary veins directly to the aorta, avoiding the left atrium and the left ventricle. This is a temporary procedure usually performed to assist other surgical procedures. (12 Dec 1998) |
| heart bypass, right | Diversion of the flow of blood from the entrance to the right atrium directly to the pulmonary arteries, avoiding the right atrium and right ventricle. This a permanent procedure often performed to bypass a congenitally deformed right atrium or right ventricle. (12 Dec 1998) |
| heart catheterization | Procedure which includes placement of catheter, recording of intracardiac and intravascular pressure, obtaining blood samples for chemical analysis, and cardiac output measurement, etc. Specific angiographic injection techniques are also involved. (12 Dec 1998) |
| heart conduction system | An impulse-conducting system composed of modified cardiac muscle and having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart. (12 Dec 1998) |
| heart defects, congenital | Imperfections or malformations of the heart, existing at birth. (12 Dec 1998) |
| heart-eating | Preying on the heart. Source: Websters Dictionary (01 Mar 1998) |
| heart failure | A condition where there is ineffective pumping of the heart leading to an accumulation of fluid in the lungs. Typical symptoms include shortness of breath with exertion, difficulty breathing when lying flat and leg or ankle swelling. Causes include chronic hypertension, cardiomyopathy and myocardial infarction. (27 Sep 1997) |
| heart failure cells | Macrophages in the lung during left heart failure that often carry large amounts of haemosiderin. See: siderophore. (05 Mar 2000) |
| heart failure in kids | <radiology> Primary cardiomyopathy, aortic outflow obstruction, coarctation, supravalvular aortic stenosis, valvular aortic stenosis, noncardiac lesion, asphyxia, TTN (transient tachypnea of newborn), perinatal brain damage (IVH) see also: neonatal congestive heart failure (12 Dec 1998) |
| heart hormone | A substance present in extracts of cardiac tissue that augments cardiac contraction; possibly adenosine, a catecholamine, or some non-specific stimulant present generally in tissues. Synonym: cardiac hormone, heart hormone. (05 Mar 2000) |
| heart injuries | General or unspecified injuries to the heart. (12 Dec 1998) |
| heart-lung machine | A combination blood pump and blood oxygenator used for temporary periods of time in cardiopulmonary bypass for cardiac surgery. (12 Dec 1998) |