Impact of left ventricular ejection fraction on occurrence of ventricular events in defibrillator patients with coronary artery disease

Aims Primary preventive implantable cardioverter defibrillator (ICD) therapy is indicated in patients with coronary artery disease (CAD) and left ventricular ejection fraction (LVEF) of <= 35%, but some patients in the major trials had LVEF in the range of 30-35%. We hypothesized that these patients constitute a lower-risk population and might derive less benefit from ICD therapy. Methods and results In this retrospective study, patients with CAD in whom an ICD was implanted for primary prevention were studied. We determined the incidence of ICD therapies in two predefined LVEF cut-off groups (<=/> 20%; <=/> 30%), predictors of ICD therapies, and overall mortality. A total of 536 patients were included: 88% male, age 63 +/- 10 years, follow-up 30 +/- 25 months. In all, 115 patients (22%) experienced appropriate ICD interventions; in 36% of them, the arrhythmia was treated with shock. Inappropriate therapy was delivered in 8%. Cumulative mortality at 5 years was 20%. Using our two cut-off levels, more ICD-therapies occurred in patients with poorer LVEF, but the difference was significant only with the cut-off value of <=/> 20%. Only 2 of 12 parameters were predictors of appropriate ICD therapy: age, odds ratio (OR) 1.047 (1.015-1.079) per year and QRS width, OR 1.014 per ms (1.004-1.024). Conclusion Refined risk stratification using different LVEF cut-off levels is not helpful in patients with CAD and LVEF <= 35%. Mortality was lower than in randomized trials in this real-world setting, probably due to better drug treatment at implant.