[Factors affecting the post-ischemic recuperation of isolated perfused rat heart]

A number of cardioplegic solutions have been described for the reduction of cellular damage during ischemic cardiac arrest. Using an isolated working rat heart model, we have attempted to precise some of the factors affecting the post-ischemic recovery of myocardial tissue after a 30-min period of total ischemia at 37 degrees C. The results indicate that procaine (1 mM) is able to afford some protective against normothermic ischemia while this protective effect remains consistently lower than that of the St. Thomas' Hospital solution (procaine + high K+ + high Mg2+; JYNGE et al., 1977). On the other hand, hearts from rats of the Wistar strain consistently exhibit a significantly better degree of recovery than do hearts from rats of the Shermann strain. When hearts were perfused at different levels of preload (1 or 2 kPa) and afterload (8 or 10 kPa), post-ischemic recovery was better in hearts with lower levels of cardiac work. Glucose, insulin and DL-propranolol which have been shown to exert a protective effect in isolated rat hearts with regional ischemia failed to protect the heart in the present experimental conditions. No clear correlation does exist between the post-ischemic recovery and the enzymatic assessment of myocardial cell damage.