Value of electrophysiologic testing in patients with previous myocardial infarction and nonsustained ventricular tachycardia

Previous studies of the value of electrophysiologic studies in patients with nonsustained ventricular tachycardia (VT) have been hampered by the inclusion of a small number of patients with various types of heart disease. This retrospective study was designed to assess the value of programmed stimulation in 205 asymptomatic patients who had had an acute myocardial infarction > 1 month before study. Inclusion was based on 24-hour Holter monitoring during which patients had to manifest ≥ 3 consecutive ventricular beats at a rate > 135 beats/min. Forty-seven (23%) patients had normal, 70 (34%) mildly impaired and 88 (43%) severely impaired left ventricular function. Programmed stimulation, using up to 3 extrastimuli, was used in each. Seventy-five patients (36%) were non-inducible, 59 (29%) had nonsustained VT (< 30 seconds), 67 (33%) had sustained monomorphic VT and 4 (2%) had either polymorphic VT or ventricular fibrillation. Eighty-two patients were not treated with antiarrhythmic drugs, 57 others were placed on a program selected empirically and 66 had therapy guided by electrophysiologic testing. Satisfactory follow-up information was gathered in 187 of the 205 patients, with a mean follow-up of 18 months. One hundred forty-two patients are alive and well, 39 had sustained VT or sudden death and 6 others had a cardiac death. Only left ventricular function discriminated those who had a sustained arrhythmia or died from those who did not. Thus, programmed stimulation did not have independent predictive value in patients with nonsustained VT. However, definite conclusions can be reached only with a large prospective study carried out in untreated patients.