Outcomes of early risk stratification and targeted implantable cardioverter-defibrillator implantation after ST-elevation myocardial infarction treated with primary percutaneous coronary intervention.

Background: Methods to identify high-risk patients and timing of implantable cardioverter-defibrillator (ICD) therapy after ST-elevation myocardial infarction need further optimization.
Methods and Results: We evaluated outcomes of early ICD implantation in patients with inducible ventricular tachycardia. Consecutive patients treated with primary percutaneous coronary intervention for acute ST-elevation myocardial infarction underwent early left ventricular ejection fraction (LVEF) assessment. Patients with LVEF >40% were discharged (group 1); patients with LVEF < or =40% underwent risk stratification with electrophysiological study. If no ventricular tachycardia was induced, patients were discharged without an ICD (group 2). If sustained monomorphic ventricular tachycardia (> or =200-ms cycle length) was induced, an ICD was implanted before discharge (group 3). Follow-up was obtained up to 30 months in all patients and up to 48 months in a subgroup of patients with LVEF < or =30% without an ICD. The primary end point was total mortality. Group 1 (n=574) had a mean LVEF of 54+/-8%; group 2 (n=83), 32+/-6%; and group 3 (n=32), 29+/-7%. At a median follow-up of 12 months, there was no significant difference in survival between the 3 groups (P=0.879), with mortality rates of 3%, 3%, and 6% for groups 1 through 3, respectively. In the subgroup of group 2 patients with LVEF < or =30% and no ICD (n=25), there was 9% mortality at a median follow-up of 25 months. In group 3, 19% had spontaneous ICD activation resulting from ventricular tachycardia.
Conclusions: Early ICD implantation limited to patients with inducible ventricular tachycardia enables a low overall mortality in patients with impaired LVEF after primary percutaneous coronary intervention for ST-elevation myocardial infarction.