Therapy for Late Post Infarction Ventricular Tachycardia

Non-sustained ventricular tachycardia (VT) in the late post myocardial infarction (MI) period (7-21 days) has been reported to be a predictor of sudden death. We suspected that patients with 3 beat VT on Holter monitoring in the late infarction period would demonstrate electrical instability at electrophysiologic studies. Forty-seven patients were identified as having at least 3 beat VT on Holter monitoring. Eighteen patients refused electrophysiologic studies or were not referred by their attending physician. The mean ejection fraction of this group was 43 +/- 16%. Eight patients have died, 3 sudden deaths in 13 +/- 5 months, a 17% incidence of sudden death. Twenty-nine patients underwent invasive electrophysiologic studies. Their mean ejection fraction was 37 +/- 7%, and 28 had inducible, 18 sustained ventricular tachycardia and 10 non-sustained VT. No complications were noted with electrophysiological testing in the post infarction patients. Using programmed electrical stimulation studies an effective antiarrhythmic agent preventing VT induction (usually experimental) could be found for each patient. After a mean follow-up of 12.5 +/- 4 months, the patient without inducible VT is alive and 26 of the 28 "inducible" patients are alive and well. Two patients died, one of stroke and one due to pump failure following a second MI. No sudden deaths were observed in this group. Two patients had breakthrough arrhythmias and were treated by alternative antiarrhythmic therapy that was also effective at the initial electrophysiologic studies. Thus, PES studies post MI are safe and may be an effective way to assess therapy for patients in the early post MI period, identified at high risk for sudden death.