| cardiac segment | Cardiac segment; medial basal segment of inferior lobe of right and left lung; can only be seen from medial and inferior surfaces since it does not reach lateral surface of lung. Synonym: segmentum basale mediale, segmentum cardiacum, cardiac segment. (05 Mar 2000) |
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| cardiac shock | A form of shock (inadequate delivery of oxygen to the tissues) that occurs secondary to the weakened pumping function of the heart. This condition may be precipitated by myocardial infarction or cardiomyopathy. Treatment includes fluid restriction, diuretics, vasopressors (dopamine) to support the blood pressure and the use of intravenous medications (dobutamine) which stimulate the heart to contract more forcefully. (27 Sep 1997) |
| cardiac skeleton | A complex framework of dense collagen forming four fibrous rings (annuli fibrosi), which surround the ostia of the valves, a right and left fibrous trigone, formed by connecting the rings, and the membranous portions of the interatrial and interventricular septa; it is found in association with the base of the ventricles, i.e., at the level of the coronary sulcus; its functions include: 1) contributing reinforcement of the valvular ostia while providing attachment for the leaflets and cusps of the valves; 2) providing origin and insertion for the myocardium; and 3) serving as a sort of electrical "insulator," separating the electrically conducted impulses of the atria and ventricles and providing passage for the common atrioventricular bundle of conductive tissue through the right fibrous trigone and membranous interventricular septum. Synonym: cardiac fibrous skeleton, cardiac skeleton, skeleton of heart. (05 Mar 2000) |
| cardiac souffle | A soft puffing heart murmur. (05 Mar 2000) |
| cardiac sound | The sounds heard over the cardiac region produced by the functioning of the heart. There are four distinct sounds: the first occurs at the beginning of systole and is heard as a "lubb" sound; the second is produced by the closing of the aortic and pulmonary valves and is heard as a "dupp" sound; the third is produced by vibrations of the ventricular walls when suddenly distended by the rush of blood from the atria; and the fourth is produced by atrial contraction and ventricular filling but is rarely audible in the normal heart. The physiological concept of heart sounds is differentiated from the pathological heart murmurs. (12 Dec 1998) |
| cardiac standstill | <cardiology> Cardiac standstill or arrest, absence of a heartbeat. Synonym: Beau's syndrome. (18 Nov 1997) |
| cardiac surgical procedures | Surgery performed on the heart. (12 Dec 1998) |
| cardiac symphysis | Adhesion between the parietal and visceral layers of the pericardium. (05 Mar 2000) |
| cardiac syncope | Fainting with unconsciousness of any cardiac cause. (05 Mar 2000) |
| cardiac tamponade | Interference with the venous return of blood to the heart due to an extensive accumulation of blood in the pericardium (pericardial effusion). Tamponade may occur as a complication of dissecting thoracic aneurysm, pericarditis, renal failure, acute myocardial infarction, hypothyroidism, autoimmune disease (for example lupus), chest trauma or a malignancy. Fluid in the pericardial sac is demonstrated by echocardiogram. Treatment involves the emergent removal of the fluid. This may be accomplished by a needle aspiration technique or emergency surgery (pericardial window). (27 Sep 1997) |
| cardiac tube | The primitive tubular heart in the embryo, before its division into chambers. (05 Mar 2000) |
| cardiac valve prosthesis | See: valve. (05 Mar 2000) |
| cardiac valvular incompetence | Failure of a valve to perform its fundamental function: insurance of one-way flow; manifested by regurgitation of blood in the opposite direction when the valve is supposed to be closed. (05 Mar 2000) |
| cardiac veins | See: anterior cardiac veins, great cardiac vein, middle cardiac vein, venae cordis minimae. (05 Mar 2000) |
| cardiac volume | The volume of the heart, usually relating to the volume of blood contained within it at various periods of the cardiac cycle. The amount of blood ejected from a ventricle at each beat is stroke volume. (12 Dec 1998) |