Effect of procaine in crystalloid and blood potassium cardioplegia solutions

Abstract

This study was undertaken to examine the effects of procaine (P) (2 g/liter) in multidose crystalloid (KCP) and blood (BCP) potassium (25 meq/liter) cardioplegia solutions during 2 hr of hypothermic (22°C) aortic occlusion. Four groups were studied: Group I KCP, P(−) n = 8, Group II KCP, P(+) ( n = 8), Group III BCP, P(−) n = 6, Group IV BCP P(+) n = 8. Change in left ventricular (LV) function was defined as percentage change in center of mass between pre- and postarrest function curves. Regional myocardial flow was measured with microspheres and myocardial metabolism monitored by lactate and oxygen utilization. Ventricular biopsies were serially obtained for myocardial ATP, creatine phosphate, calcium, water content, and ultrastructure study. LV function percentage recovery was 62 ± 4% in Group I, 79 ± 5% in Group II, 81 ± 4% in Group III and 72 ± 4% in Group IV. Myocardial regional flow did not show significant differences between groups P(−) and P(+) though KCP and BCP groups showed different patterns of reperfusion. Lactate and oxygen utilization did not show significant differences between groups. In all groups ATP and calcium were well preserved and mild edema formation was observed at reperfusion. Ultrastructural preservation was good except in Group I where myofilament breakdown was present. Procaine was effective in obtaining spontaneous recovery of normal electrical activity. In conclusion, BCP without procaine significantly improved myocardial protection over similar KCP. Procaine had a significant additive effect in KCP and no additive effect in BCP.