Programmed electrical stimulation for risk stratification of patients with ischemic cardiomyopathy

Patients with ischemic cardiomyopathy (ICM) are at an increased risk for sudden death. Although earlier trials used programmed electrical stimulation (PES) for risk stratification, more recent data demonstrate the benefit of implantable cardiac defibrillators (ICDs) in selected patients with reduced left ventricular ejection fraction (LVEF) without performing PES. However, little is known about the outcome of non-inducible patients. The purpose of this study was to evaluate the efficacy of PES for mortality risk stratification in patients with ICM.

All consecutive patients who met the inclusion criteria (history of coronary artery disease, LVEF≤35%, and absence of documented spontaneous sustained ventricular tachycardia or aborted sudden cardiac death) were included in the study. The stimulation protocol involved up to three extrastimuli from two different sites in the right ventricle, with 180 ms as the shortest coupling interval. The primary endpoint was overall survival.

A total of 198 patients were included in the study; of these, 60 exhibited negative (-)PES, and 138 had positive (+)PES and also underwent ICD implantation. The mean follow-up duration was 4.5 years. There was no difference in age or LVEF between the patient groups. We found a trend towards an increased 5-year survival rate in the (+)PES group in whom ICD implantation had been performed (p=0.058). Survival was significantly better in patients under 68 year olds in the (+)PES group in whom ICD implantation was performed (hazard ratio=0.3, p=0.01). The survival rate of patients ≥68 years old was similar in both groups (p=0.95).

Non-inducibility during PES does not predict the prognosis of patients with ischemic cardiomyopathy.