Outcomes of Early Risk Stratification and Targeted Implantable Cardioverter-Defibrillator Implantation After ST-Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention

Abstract

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 ≤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 (≥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 ≤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 ≤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.