The results of serial electrophysiologic testing in patients with sustained ventricular tachycardia or ventricular fibrillation indicate that if the arrhythmia is suppressible with antiarrhythmic drugs, the prognosis is better than when arrhythmias continue to be inducible despite antiarrhythmic drug treatment. Whether electrophysiologically guided antiarrhythmic drug therapy improves outcome or merely selects groups of patients with good and bad prognosis, is not known. To answer this question, a prospective randomized trial was conducted with 166 patients (sustained ventricular tachycardia n = 84; primary ventricular fibrillation n = 46; syncope n = 36). When the arrhythmia was inducible by programmed stimulation during control, patients were allocated to receive either electrophysiologically guided antiarrhythmic drug therapy (group I), or metoprolol (daily dose up to 200 mg) without invasive testing (group II). Patients with non-inducible arrhythmias were also treated with metoprolol (group III).
Results: During a follow-up of 10 +/- 8 (SD) months, there were arrhythmia recurrences in 30 patients, and sudden cardiac death in 17. Follow-up did not differ between group I (n = 59) and group II (n = 53). There was a tendency for the outcome to be better in patients of group III (n = 54) than in those of group II (Log-rank test p = 0.057). In group I, patients whose arrhythmias became suppressed did much better during follow-up than those with still inducible arrhythmias (p less than 0.0001). Thus, while invasive testing is a good predictor of outcome, electrophysiologically guided antiarrhythmic drug therapy is not better than a beta blocker in patients with sustained ventricular tachyarrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)