Left ventricular function improvement after prophylactic implantable cardioverter-defibrillator implantation in patients with non-ischaemic dilated cardiomyopathy

Abstract

To assess the incidence and prognostic significance of left ventricular (LV) function improvement in patients with non-ischaemic dilated cardiomyopathy (DCM) and prophylactic implantable cardioverter-defibrillator (ICD). A total of 123 patients with DCM and echocardiographic follow-up assessments within 1 year after prophylactic ICD implant were retrospectively studied at our institution. All patients had New York Heart Association class II or III symptoms in the presence of a LV ejection fraction of 23 ± 6% (range: 9-35%) despite optimized medical therapy for at least 3 months prior to ICD implant. Left ventricular function improvement was defined as an increase of LV ejection fraction of more than 5% to more than 35% combined with a decrease LV end-diastolic diameter of at least 5 mm. Left ventricular function improvement after prophylactic ICD implant was found in 30 of 123 patients (24%). Multivariate logistic regression revealed recent onset DCM with symptoms ≤9 months as the only significant predictor of LV function improvement [odds ratio: 6.89; 95% confidence interval (CI): 2.43-21.99, P = 0.0002]. During 74 months mean follow-up, total mortality was higher in patients without vs. with LV function improvement [hazard ratio (HR): 3.75; 95% CI: 1.14-12.31, P = 0.0034], while the incidence of appropriate ICD therapies was similar in both groups in the early phase after prophylactic ICD implant (HR: 1.15; 95% CI: 0.57-2.33, P = 0.70). The incidence of appropriate ICD therapies decreased to ∼1% per year after LV function improvement had occurred. Recently diagnosed DCM predicts LV function improvement after prophylactic ICD implant. Overall survival was significantly better in patients with vs. without LV function improvement, while appropriate ICD therapy rates were similar in both groups in the early phase after prophylactic ICD implantation before LV function improvement occurred.