Sustained ventricular tachycardia and ventricular fibrillation complicating non-ST-segment-elevation acute coronary syndromes

Abstract

Background: Ventricular arrhythmias remain a lethal complication of acute coronary syndromes (ACS). However, the incidence and prognosis of sustained ventricular tachycardia/ventricular fibrillation (VT/VF) in contemporary non-ST-segment-elevation (NSTE) ACS populations are not well described.

Methods and results: We examined the incidence of VT/VF and subsequent survival among 9211 patients enrolled in the Early Glycoprotein IIb/IIIa Inhibition in NSTE ACS (EARLY ACS) trial. The cumulative incidence of VT/VF was 1.5% (n=141); 0.6% (n=55) had VT/VF ≤48 hours after enrollment, and 0.9% (n=86) had VT/VF >48 hours after enrollment. Patients with VT/VF more frequently had prior heart failure, an ejection fraction <30%, and triple-vessel coronary artery disease. Predictors of sustained VT/VF were similar regardless of the timing of VT/VF (≤48 versus >48 hours). Patients with VT/VF ≤48 hours after enrollment had higher 30-day mortality than those who did not have VT/VF ≤48 hours (13.0% versus 2.2%; adjusted odds ratio, 6.73; 95% confidence interval, 2.68-16.9). The increased risk of death associated with VT/VF ≤48 hours persisted at 1 year. The risk of mortality, relative to patients without VT/VF, was greater for patients with VT/VF >48 hours (hazard ratio, 20.70; 95% confidence interval, 15.39-27.85) than for those with earlier VT/VF (hazard ratio, 7.45; 95% confidence interval, 4.60-12.08; P=0.0003). The frequency of arrhythmic death was higher in patients with VT/VF than in those without VT/VF (26.4% versus 6.9%).

Conclusions: Sustained VT/VF is infrequent after NSTE ACS but is as likely to occur after 48 hours as within the first 48 hours. The marked increase in all-cause death among NSTE ACS patients with both early and late sustained VT/VF raises important considerations for aggressive monitoring beyond 48 hours and interventions to prevent arrhythmic death in these patients.

Clinical trial registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00089895.