Kaplan–Meier patient survival from death due to any cause: comparison between subgroups. Comparison by means of log-rank test of cumulative 6-year survival from death due to any cause. (A) In the CRT-D group, patients with non-ischaemic cardiomyopathy (blue line) have a higher survival rate than those with ischaemic cardiomyopathy (red line) (P = 0.026). (B) In the ICD-only group, patients with non-ischaemic cardiomyopathy (blue line) have a survival rate similar to patients with ischaemic cardiomyopathy (red line) (P = 0.918). (C) Patients of the CRT-D group with LBBB QRS morphology (green line) showed better survival than patients of the CRT-D group with non-LBBB QRS morphology (red line) (P = 0.015); patients of the CRT-D group with LBBB QRS morphology showed better survival than patients of the ICD-only group (blue line) (P = 0.017); and patients of the CRT-D group with non-LBBB QRS morphology have a survival rate similar to the ICD-only group (P = 0.733). CRT-D, cardiac resynchronization therapy plus defibrillator device; ICD, implantable cardioverter defibrillator; LBBB, left bundle branch block.