[Reperfusion arrhythmias in valvular patients undergoing extracorporeal surgery and pretreated with captopril]

After the ischemia-reperfusion process in extracorporeal cardiac surgery there are, among several phenomena, some reperfusion arrhythmias which are influenced by a varied series of mechanisms. These arrhythmias have been related to the release of oxygen-derived free radicals during the first moments of reperfusion. Thus, a previous administration of free-radical scavengers might be beneficial, among which captopril has been included with good results in human studies in vitro and in animals in vivo. The aim of this study was to evaluate the influence of pretreatment with captopril on the prevention of reperfusion arrhythmias in patients undergoing valvular cardiac surgery.

30 patients were randomly allocated to pretreatment with either captopril (CTP group, n = 15) or without captopril (CON group, n = 15). Exclusion criteria (left ventricular ejection fraction < 40%, evidence of angiographic coronary disease, prior myocardial infarction and preoperatory myocardial infarction). The dose of captopril administered was 12.5 mg every 8 hours orally, from 24 hours before surgery. A Holter register was used to analyze the ventricular arrhythmias (extrasystoles, salvos, tachycardia and fibrillation) during the first hour of reperfusion. The need for cardioversion was examined and the number of shocks needed. These events were related to changes in blood analyses from coronary sinus samples to determine creatine phosphokinase, activity of the angiotensin converting enzyme and cyclic adenosine monophosphate, before aortic clamping and after the heart was rewarmed.

No significant differences were found in the number of ventricular arrhythmias. 60% of the patients with captopril and only 40% of the patients without it (non significant) had spontaneous defibrillation without electric shock; in those cases in which it was necessary, 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 monophosphate increase, there is no significant correlation between the other arrhythmias and the analytical data studied.

These data suggest that captopril, given before cardiac surgery, has little or no protector 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 necessary for defibrillation, without negative effects.