Lorcainide Therapy for the High-Risk Post Myocardial Infarction Patient JOHN C:. SOMBERG, MD, BRENDA BUTLER, BA, VILMA TORRES, MD, DAVID FLOWERS, MD, DAVID TEPPER, BA, DEBORAH KEEFE, MD, and DENNIS S. MIURA, MD, PhD Nonsustained ventricular tachycardia (VT) in the late period (7 to 21 days) after myocardial infarction (Ml) is,reported to be a predictor of sudden death. Patients with 3-beal VT on Holter monitoring in the late infarction pertod would be suspected to dem- onstrate electrical instability on electrophysiologtc studies. Forty-seven patients were identifted as having at least 3-beat VT on Holter monitoring. Etghteen patients refused etectrophysiologic studies or were not referretd. Eight patients died; 3 were sudden deaths in 13 f 5 months, a 17% incidence. Twentyinine patients underwent invasive electro- physiologic studies and 28 had inducible VT, 18 sustained and 1.0 nonsustained. Lorcainide pre- vented VT induction in 21 of the 28 patients, whereas 12 of the 22 patients studied on procainamide were protected. Lidocaine, tested in 21 patients, pre- vented VT induction in only 5. Lorcainide and pro- cainamide prolonged refractorktess in those patients protected at programmed electrical stimulation The assessment of antiarrhythmic therapy has under- gone considerable change. Patients with life-threatening symptomatic ventricular tachycardia (VT) are under- going intensive studies to determine optimum antiar- rhythmic therapy. Instead of blind initiation of drug therapy, more patients are being assessed before and after therapy. Many patients do not have frequent enough ambient ectopy and runs of VT to permit a statistically adequate assessment of the efficacy of From the Cardiac Antrythmia Service, Cardiology Division, Departments of Medicine and Pharmacolcgy, Albert Einstein College of Medicine, Bronx, New York. Dr. Somberg is an Established Investigator of the American Heart Associitkm. This study was supported in part by a grant from Janssen R & D, Inc. Requests for reprints: John C. Somberg, MD, Cardiology Division, Albert Einstein College of Medicine, 1300 Morris Park Avenue, F-208, Bronx, New York 10461. (PES), whereas the QT interval was prolonged in patients in whom VT could still be induced. Twenty-seven of the 28 patients were placed on drugs predtcted to be effective by PES studies, 19 on lorcainide. After a mean follow-up of 12.5 f 4 months the patient with noninducible arrhythmia Is alive and 28 of the 28 patients with inducible ar- rhythmia are alive and well. Two patients died, 1 of stroke and 1 of pump failure afler a second MI. No sudden deaths were observed in this group. Two patients had breakthrough arrh,ythmias and were treated by alternative antiarrhythmic therapy that was also effective on initial electrophysiologic studies. Thus, PES studies after MI are safe and may be an effective way to determine therapy for patients in the post-Ml period, identified at high risk for sud- den death. Furthermore, lorcainide appears to be safe and effective when its selection is guided by electrophysiologic studies. (Am J Cardiol 1984;54:37B-428) therapy using Holter techniques. This problem is fur- ther compounded by the marked variation in ectopic frequency.i For these reasons, many investigators and those responsible for therapeutic decisions in patients with symptomatic VT have turned to invasive electro- physiologic testing. These tests identify those at risk for sudden death,213 and if pharmacologic therapy is se- lected by this approach, these tests predict a successful outcome.3y4 Potentially life-threatening ventricular arrhythmias are frequently noted after acute myocardial infarction (MI). These arrhythmias occurring in the early infarc- tion period can be treated effectively and may not cor- relate with late out-of-hospital VT and sudden cardiac death.5ys However, arrhythmias noted in the late phases of an acute MI may denote a heightened state of myo- cardial electrical instability.y-l’J Recent studies report that VT and frequent premature ventricular contrac- tions (PVCs) (>lO/hour on the average) are multivar- 378