Incidence and short-term prognosis of late sustained ventricular tachycardia after myocardial infarction: Results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI-3) data base

Background There is little epidemiologic information from large multicenter databases on sustained monomorphic ventricular tachycardia occurring after the initial 48 hours of myocardial infarction. Methods We reassessed its incidence and short-term prognosis in 16,842 patients with a definite myocardial infarction enrolled in the Gruppo Italiano per lo Studio della Soprovvivenza nell'Infarto Miocardico (GISSI-3) trial. Results The incidence rate of late sustained ventricular tachycardia by 6 weeks was around 1%. Older age, a history of hypertension, diabetes, and myocardial infarction, nonadministration of lytic therapy, Killip class >1, ≥6 leads with ST-segment elevation, higher heart rate, and bundle branch block on admission were significantly more frequent among patients with than without late sustained ventricular tachycardia. Patients with ventricular tachycardia had a more complicated course in-hospital and posthospital to 6 weeks than the reference group did. The arrhythmia was associated with a significant excess of pump failure, atrial flutter-fibrillation, asystole, atrioventricular block, ventricular fibrillation within the first 48 hours of myocardial infarction, and recurrent ischemic events. Larger left ventricular end-systolic volumes and lower ejection fractions were more frequent among ventricular tachycardia patients than in the reference group by 6 weeks. Death rates by 6 weeks were 35% for patients with ventricular tachycardia and 5% for those without the arrhythmia. Irrespective of the stratification of patients by site and type of infarct and presence/absence of bundle branch block, the occurrence of the arrhythmia was associated with reduced 6-week survival. Conclusion In a proportional hazard regression model late sustained ventricular tachycardia was retained as a strong, independent predictor of 6-week mortality after myocardial infarction (hazard ratio 6.13, 95% confidence interval 4.56-8.25).