Study on myocardial contractility after cardiopulmonary bypass versus cardioplegic arrest in an air-ejecting in vivo heart model.
Cardiac function was assessed in a working in vivo canine heart preparation. Minute work and myocardial oxygen consumption (MVo2) were measured after a two-hour period of hypothermic hyperkalemic crystalloid cardioplegic arrest in one group of dogs (Group 1, N = 6) and in another group of dogs on cardiopulmonary bypass (CPB) alone (Group 2, N = 6). Results indicate that at an afterload of 50 cm H2O, minute work was the same in all hearts but MVo2 was significantly higher in Group 1 hearts at all levels of preload. At higher afterloads, both minute work and MVo2 were significantly greater in Group 1 hearts over the range of preloads tested. Ventricular compliance was decreased in Group 1 over the range of preloads studied. These results suggest that hearts undergoing cardioplegic arrest had better left ventricular contractility than hearts undergoing CPB alone.
D000818:Animals; D002315:Cardiopulmonary Bypass; D004285:Dogs; D006321:Heart / Q000502:physiology; D006324:Heart Arrest, Induced; D008954:Models, Biological; D009200:Myocardial Contraction; D010101:Oxygen Consumption; D013318:Stroke Volume