VAGUS NERVE-STIMULATION AS A METHOD TO TEMPORARILY SLOW OR ARREST THEHEART

Background. Electrical stimulation of nerves is used to study nervous system and body function relationships. Electrical stimulation of the vagus nerve was used to slow the heart during coronary artery bypass g rafting. Methods. A 48-year-old man with multivessel coronary artery d isease, scheduled for revascularization, gave informed consent for the surgeon to stimulate his vagus nerve. As part of the operation the le ft internal mammary artery was harvested as a pedicle and the patient was placed on cardiopulmonary bypass. The vagus nerve was isolated as it crossed the aorta just lateral to the phrenic nerve. Pacing wires w ere placed (1 cm apart) allowing prodromic conduction. With the patien t fully supported by cardiopulmonary bypass and after administration o f neostigmine (2.5 mg intravenously) eight separate continuous 5-secon d electrical pulse trains (25 Hz, 20 V, pulse width of 0.1 ms) were de livered to the nerve with 30-second rest periods between each stimulat ion. During the periods of stimulation the mammary artery to left ante rior descending artery anastomosis was completed. Results. Electrical stimulation caused cessation of the heartbeat, termination of the same resulted in normal sinus rhythm, although it was slowed by the neosti gmine. Suturing of the anastomosis was done during periods of stimulat ion. Additional anastomoses were completed using cardiopulmonary bypas s- delivered cardioplegia and aortic cross-clamping. Conclusions. Elec trical stimulation of the vagus nerve slowed and temporarily arrested the heart for brief periods to allow critical placement of anastomotic sutures. (C) 1997 by The Society of Thoracic Surgeons.