| 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) |
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| 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 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) |
| heart-lung transplantation | The simultaneous, or near simultaneous, transference of heart and lungs from one human or animal to another. (12 Dec 1998) |
| heart massage | Rhythmic compression of the heart by pressure applied manually over the sternum (closed heart massage) or directly to the heart through an opening in the chest wall (open heart massage). It is done to reinstate and maintain circulation. (12 Dec 1998) |
| heart murmur | A finding on physical examination of the heart that can, in some cases, indicate the presence of cardiac disease. Murmurs result from vibrations set up in the bloodstream and the surrounding heart and great vessels as the result of turbulent flow. (27 Sep 1997) |
| heart murmurs | A sound generated by disturbed blood flow through the heart manifested as "turbulence". Turbulence is an irregular condition of motion caused by local vibrations of the wall of a vessel or heart chamber. Heart murmurs are usually detectable in ventricular outflow obstruction and in various types of heart valve disease and are differentiated from heart sounds, a physiological concept. (12 Dec 1998) |