| 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) |
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| 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-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) |
| 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) |
| heart muscle | <anatomy> Tissue specialised for contraction. See twitch muscle, catch muscle: Cardiac muscle (heart muscle) is a striated but involuntary muscle responsible for the pumping activity of the vertebrate heart. The individual muscle cells are joined through a junctional complex known as the intercalated disc and are not fused together into multinucleate structures as they are in skeletal muscle. Skeletal muscle is a rather non-specific term usually applied to the striated muscle of vertebrates that is under voluntary control. The muscle fibres are syncytial and contain myofibrils, tandem arrays of sarcomeres. Smooth muscle is muscle tissue in vertebrates made up from long tapering cells that may be anything from 20-500m long. Smooth muscle is generally involuntary and differs from striated muscle in the much higher actin/myosin ratio, the absence of conspicuous sarcomeres and the ability to contract to a much smaller fraction of its resting length. Smooth muscle cells are found particularly in blood vessel walls, surrounding the intestine (especially the gizzard in birds) and in the uterus. The contractile system and its control resemble those of motile tissue cells (for example fibroblasts, leucocytes) and antibodies against smooth muscle myosin will cross react with myosin from tissue cells, whereas antibodies against skeletal muscle myosin will not. See: dense bodies. (18 Nov 1997) |
| heart position | A description of the heart's assumed electrical habitus based upon the form of the QRS complexes in leads aVL, aVF, V1, and V6. Sometimes loosely (and inaccurately) used to describe the frontal plane electric axis. Synonym: heart position. (05 Mar 2000) |