Cardiac effects of vecuronium and pancuronium during halothane anaesthesia

The cardiac effects of equipotent doses of pancuronium and vecuronium (Org NC 45) were compared in 20 patients, anaesthetized with halothane. Heart rate and arterial pressure were recorded and the systolic time intervals were evaluated from simultaneous tracings of ECG, phonocardiogram and carotid pulse curve. Pancuronium 0.08 mg kg-1 caused a significant increase in heart rate (20%), insignificant changes in arterial pressure and significant changes in systolic time intervals compatible with a minor positive inotropic action. The equipotent dose of vecuronium (0.057 mg kg-1) caused no significant changes in heart rate, arterial pressure or systolic time intervals.