Cardiac function was assessed in a working in vivo canine heart preparation. Minute work and myocardial oxygen consumption (MV(O2)) 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 MV(O2) was significantly higher in Group 1 hearts at all levels of preload. At higher afterloads, both minute work and MV(O2) 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 heart undergoing cardioplegia arrest had better left ventricular contractility than hearts undergoing CPB alone.
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
- Cardiology and Cardiovascular Medicine