Effect of electrophysiological testing on ejection fraction during cardioverter/defibrillator implantation.

To evaluate the effect of repeated induction of ventricular tachycardia or ventricular fibrillation, or both, in patients with poor left ventricular function, we performed intraoperative two-dimensional echocardiography in 6 patients undergoing implantation of the automatic implantable cardioverter/defibrillator. Changes in left ventricular ejection fraction in sinus rhythm were assessed before the first inducible ventricular arrhythmia and after a mean of 6 +/- 1.9 (SD) episodes of ventricular tachycardia or ventricular fibrillation. During the procedure no significant change in mean ejection fraction was observed (28 +/- 14 versus 27 +/- 17%). Only 1 of the 6 patients studied had a change in ejection fraction greater than 3% (a decrease from 20 to 11%). In an overall clinical series of 38 primary implants or generator changes (including electrophysiological testing) in 29 patients, 1 patient recovered after postoperative inotropic support and 1 died of acute postoperative ischemic heart failure. We conclude that ventricular arrhythmias induced during automatic implantable cardioverter/defibrillator implantation have no immediate deleterious effects on ejection fraction in most patients with compromised left ventricular function and without ongoing ischemia.