ROLE OF PROCAINE AND WASHED RED-CELLS IN THE ISOLATED DOG HEART PERFUSED AT 5-DEGREES-C

Abstract

Isolated dog hearts were perfused for 24 h at 5.degree. C with 1 of 3 solutions: plain Krebs solution, Krebs solution containing 167 mg/l of procaine hydrochloride, or Krebs-procaine solution with washed red cells (hematocrit 2%). Coronary vascular resistance (CVR) of hearts perfused with Krebs solution alone increased sharply between the 8th and 12th h of perfusion and then stabilized. Increase of myocardial firmness paralleled the increase of CVR. The addition of procaine to Krebs perfusate kept the heart flaccid and suppressed the step-like increase in CVR, but failed to improve significantly the preservation of the hearts. The addition of washed red cells to Krebs perfusate kept CVR near baseline level, improved coronary perfusion flow, doubled myocardial O2 consumption, reduced edema formation and improved left ventricular stroke work (LVSW) of the preserved heart. This improvement seems mostly related to a mechanical effect of red blood cells on capillary flow distribution of the heart.