Long-Term Arrhythmia-Free Survival in Patients with Severe Left Ventricular Dysfunction and No Inducible Ventricular Tachycardia Post Myocardial Infarction
Background—A negative electrophysiology study (EPS) may delineate a sub-group of patients with severely impaired left ventricular ejection fraction (LVEF) who are safe long-term without an implantable-cardioverter defibrillator (ICD).
Methods and Results—Consecutive patients treated with primary percutaneous coronary intervention for ST-elevation myocardial infarction (STEMI) underwent early (median 4 days) LVEF assessment. Patients with LVEF≤40% underwent EPS. A prophylactic ICD was implanted for a positive [inducible monomorphic ventricular tachycardia (VT)] but not a negative (no inducible VT or inducible ventricular fibrillation (VF)/flutter) EPS result. Patients who would have become eligible for a late primary prevention ICD with LVEF≤30% or ≤35% with NYHA class II/III heart failure (HF) were included and analysed according to EPS result. Patients with LVEF>40%, ineligible for EPS, were followed as controls (n=1,286). The primary endpoint was survival free of death or arrhythmia (resuscitated cardiac arrest or sustained VT/VF). EPS performed in 128 patients with LVEF≤30%/≤35% & HF was negative in 63% (n=80) and positive in 37% (n=48). ICDs were implanted in <0.1%, 4% and 90% of control, EPS-negative and EPS-positive patients, respectively. The distribution of time to death or arrhythmia was comparable in control patients and EPS-negative patients with LVEF≤30%/≤35% & HF (P=0.738); who both differed significantly from EPS-positive patients (P<0.001). At 3 years 91.8±3.2%, 93.4±1.0% and 62.7±7.5% of control, EPS-negative and EPS-positive patients were free of death or arrhythmia, respectively.
Conclusions—Re-vascularised STEMI patients with severely impaired LV function but no inducible VT have favourable long term prognosis without the protection of an ICD.
- Received July 22, 2013.
- Revision received November 20, 2013.
- Accepted November 25, 2013.