ELECTROCARDIOGRAPHIC RECORDING, ATRIAL-PACING, AND DEFIBRILLATION IN THE COURSE OF ELECTROPHYSIOLOGIC STUDIES USING THE ESOPHAGUS

Background: The purpose of this study was to evaluate the use of a new quadripolar esophageal electrode system during electrophysiologic studies, with regard to transesophageal ECG recording, atrial pacing, and countershock of induced sustained ventricular tachyarrhythmias, Methods: The esophageal system was electively positioned in 29 patients undergoing electrophysiological studies for investigation of life-threatening ventricular arrhythmias. Results: One patient was unable to tolerate the esophageal system after its initial successful placement and the electrode was withdrawn. High-quality esophageal ECG recordings were obtained in the remaining 28 patients. Transesophageal atrial pacing was attempted in four patients and successful capture was achieved in all four patients. During programmed ventricular stimulation, electric countershock was required for termination of five episodes of induced ventricular tachycardia and 10 episodes of induced ventricular fibrillation. Successful transesophageal countershock of the five episodes of ventricular tachycardia and of nine of 10 episodes of ventricular fibrillation were effected, with minimal delay, using a maximal delivered transesophageal energy of 100 J. In one patient with induced ventricular fibrillation, successful transthoracic defibrillation was achieved with a single shock of 200 J delivered energy, transesophageal countershock was not attempted. Conclusions: This esophageal system provides high-quality ECG recordings with the facility for atrial pacing. It also permits low-energy transesophageal defibrillation of ventricular tachyarrhythmias and should prove to be a useful adjunct in electrophysiologic studies and resuscitation.