REPERFUSION ARRHYTHMIAS IN VALVULAR PATIE NTS UNDERGOING EXTRACORPOREAL CARDIAC-SURGERY AND PRETREATED WITH CAPTOPRIL

Introduction and objectives. After the ischemia-reperfusion process' i n extracorporeal cardiac surgery there are, among several phenomena, S ome reperfusion arrhythmias which are influenced by a varied series of mechanisms. These arrhythmias have been related to the release of oxy gen-derived free radicals during the first moments of reperfusion. Thu s, a previous administration of free-radical scavengers might be benef icial, among wich captopril has been included with good results inhuma n studies in vitro and in animals in vivo. The aim of this study was t o evaluate the influence of pretreatment with captopril on the prevent ion of reperfusion arrhythmias in patients undergoing valvular cardiac surgery. Methods. 30 patients were randomly allocated to pretreatment with either captopril (CTP group, n = 15) or without captopril (CON g roup, n = 15). Exclusion criteria (left ventricular ejection fraction < 40%, evidence of angiographic coronary disease, prior myocardial inf arction and peroperatory myocardial infarction). The dose of captopril administered was 12.5 mg every 8 hours orally, from 24 hours before s urgery. A Holter register was used to analyze the ventricular arrhythm ias (extrasystoles, salves, tachycardia and fibrillation) during the f irst hour of reperfusion. The need for cardioversion was examined and the number of shocks needed. These events were related to changes in b lood analyses from coronary sinus samples to determine creatine phosph okinase, activity of the angiotensin converting enzyme and cyclic aden osine monophosphate, before aortic clamping and after the heart was re warmed. Results. No significant differences were found in the number o f ventricular arrhythmias. 60% of the patients with captopril and only 40% of the patients without it (non significant) had spontaneous defi brillation without electric shock; in those cases in which it was nece ssary, the number of shocks was less in the captopril group (p < 0.05) . Excepting the significant correlation (p < 0.01) that we have found between ventricular fibrillation and the cyclic adenosine monophosphat e increase, there is no significant correlation between the other arrh ythmias and the analytical data studied. Conclusions. These data sugge st that captopril, given before cardiac surgery, has little or no prot ector effect on reperfusion ventricular arrhythmias in extracorporeal cardiac surgery, though in patients treated with captopril there is a greater possibility of spontaneous defibrillation and fewer shocks nec essary for defibrillation, without negative effects.