Effects of captopril on the ACE-tissular system and on models of experimental ischaemia in isolated rabbit hearts.

In this study the authors evaluated the effect of captopril on coronary flow (CBF) dP/dT ratio and on reperfusion ventricular hyperkinetic arrhythmia (VHA) in 15 isolated and perfused (Langendorff's procedure) rabbit hearts following acute experimental ischaemia. The final goal was to determine whether pretreatment with captopril (administered before induced ischaemia or during the perfusion period) could protect the heart from the effects induced by acute ischaemia. Acute ischaemia was produced through 15-min ligation of the anterior descending coronary artery at its origin. After the ischaemic period, the hearts were subjected to a perfusion procedure for 45 min. Isolated hearts were connected to an intraventricular transducer system to evaluate intraventricular pressure curves, associated with a monitoring electrocardiogram system. Renin activity was detected by the RIA method from perfusion fluid samples. The 15 isolated and perfused rabbit hearts were subgrouped into 3 experimental groups as follows: Experiment No. 1: in this model the effects of acute induced ischaemia were evaluated in 5 rabbits without treatment and used as controls. At the end of the ischaemic period a relevant percent decrease in CBF (-36%) and in Dp/dT ratio (-33%) was found; after perfusion period a further percent decrease in CBF (-41%) and in Dp/dT ratio (-41%) was observed. Renin activity increased significantly only during the ischaemic period. In all the rabbits ventricular premature beats (VPB) were found and in 3 rabbits ventricular fibrillation (VF) was also detected.(ABSTRACT TRUNCATED AT 250 WORDS)