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.