Haemodynamic and Metabolic Effects of Gallopamil as Additive to Calcium-containing and Calcium-free Cardioplegic Solutions in Mature Pig Hearts

Abstract

Myocardial haemodynamic and metabolic effects of the calcium-channel blocker gallopamil as additive to calcium-containing (St Thomas Hospital, STH) and calcium-free (Bretschneider procaine-containing, BRT) crystalloid cardioplegic solutions were evaluated. Adult pig hearts (weight 0.330 ± 0.033 kg) were randomized to four groups and perfused with 1 litre of cold (4°C) cardioplegic solution; group A: BRT without gallopamil, n = 9, group B: BRT with gallopamil (0.4 μM), n = 8, group C: gallopamil-free STH, n = 8, and group D: STH with gallopamil (0.4 μM), n = 8. After storage at 4°C for 6 hours the hearts were reperfused with blood/Ringer solution in a modified Langendorff model for 60 min. Developed left ventricular pressure, rate-pressure product and +dP/dt were lower in gallopamil-treated hearts during reperfusion (p < 0.05), as were oxygen extraction and oxygen uptake (p < 0.05) and lactate release (p < 0.05). Myocardial blood flow was greater in gallopamil-treated hearts (p < 0.05). In hearts comparable in size and anatomy to the human heart, gallopamil added to both cardioplegic solutions reduced cardiac function and oxygen uptake despite increased myocardial blood flow. The findings suggest reduced myocardial protection after addition of gallopamil to cardioplegic solutions.