Effect of β-blocking therapy on outcome in the Multicenter Unsustained Tachycardia Trial (MUSTT)

Background - β-Blockers are known to reduce total mortality and sudden death in survivors of recent myocardial infarction. The effects of these agents in patients at high risk for sudden death with remote infarction are not clear. Methods and Results - We analyzed the effect of β-blockers on outcomes in 2096 patients with coronary artery disease, ejection fraction ≤40%, and spontaneous nonsustained ventricular tachycardia enrolled in the Multicenter UnSustained Tachycardia Trial (MUSTT). Forty-five percent of 702 patients with inducible sustained ventricular tachyarrhythmia and 35% of 1394 patients without inducible tachycardia were discharged from hospital receiving β-blockers. Patients treated with β-blockers were younger and had higher ejection fractions, higher rates of recent angina, and more recent infarction. β-Blockers were associated with decreased total mortality for the entire study population (5-year mortality 50% with β-blockers versus 66% without β-blockers; adjusted P=0.0001). The mortality benefit associated with β-blockers was present in patients with and without inducible tachycardia, except those treated with implantable defibrillators. There was no significant effect of β-blocker therapy on the rate of arrhythmic death or cardiac arrest (adjusted P=0.2344). Conclusions - β-Blocking agents have beneficial effects on survival of patients having characteristics of those enrolled in the MUSTT trial. These effects do not appear to be due to a specific antiarrhythmic effect of β-blockers. The beneficial effects of β-blockers were demonstrable in all patients except those treated with implantable defibrillators.