EFFECT OF PROPRANOLOL ON THE VENTRICULAR ARRHYTHMIAS INDUCED BY HYPERCARBIA DURING HALOTHANE ANAESTHESIA IN MAN

The effects of propranolol on arterial blood pressure, heartrate, and cardiac rhythm during ventricular arrhythmias initiatedby hypercarbia were investigated in thirteen subjects during1 per cent halothane anaesthesia. Propranolol was consistentlyeffective in the treatment of ventricular arrhythmia inducedby hypercarbia in all subjects. The successful use of propranololsuggests that the mechanism for ventricular arrhythmia producedby respiratory acidosis during halothane anaesthesia was relatedto beta adrenergic receptors. Blockade of these receptors bybeta adrenergic agents decreased markedly the sensitizationof myocardium to sympathetic stimulation.