Effects of nadolol on arrhythmias during laparoscopy performed under general anaesthesia

Abstract

There is a well recognized incidence of potentially serious cardiac arrhythmias during general anaes-thesia for gynaecological laparoscopy [1]. This incidence may reflect the effects of volatile anaesthetic agents, but other precipitating factors include increased sympathoadrenal activity secon-dary to surgical stimulation of laparoscopy, and reflex increase in cardiac vagal tone, secondary to peritoneal manipulation, which may lead to severe bradycardia, asystole, or both [2]. Previous studies have suggested that prior administration of beta-adrenoreceptor blocking compounds may reduce the frequency of arrhyth-mias during halothane anaesthesia [3]. The pre-sent study examined the effects of pretreatment with nadolol on the incidence of arrhythmias in patients undergoing laparoscopy. METHODS AND RESULTS Eighty-six patients (mean age 34.2 yr) gave in-formed written consent to the study. None had evidence of cardiac disease and none was receiving cardioactive drugs. Twelve hours before lapar-oscopy, patients were administered either nadolol or placebo tablets by mouth in a double-blind randomization schedule. The first 40 patients were given nadolol 40 mg or placebo, but as profound bradycardia was noted in a few, the dose of nadolol was reduced to 20 mg in the subsequent randomized group. All patients were premedi-cated with papaveretum 15 mg with hyoscine 0.3 mg i.m. 1 h before anaesthesia