Data from all patients with ischemic or non-ischemic cardiomyopathy implanted in primary prevention with a CRT-D in 12 French centers were considered for analysis (2002–2012).
Out of the 1516 patients with DT information available, DT was performed in 958(63%) patients. Compared to DT − patients, DT + patients presented no significant differences in terms of age (65.1 ± 10.8 vs 64.7 ± 10.3 years, p = 0.45), LVEF (25%[20.0–30.0] vs 25%[20.5–30.0], p = 0.30), or etiologies of heart failure (ischemic: 49.6% vs 46.9%, p = 0.32). By contrast, DT + patients were less likely to present atrial fibrillation (25.3% vs 33.4%, p = 0.001), renal insufficiency (eGFR < 60 ml/min in 45.3% vs 51.7%, p = 0.04) and NYHA functional class ≥ III (68.9% vs 77.4%, p = 0.0006). All of the three perioperative deaths occurred in the DT + group and were related to DT itself. After a mean follow-up of 3.1 ± 2.1 years, the adjusted incidence of overall mortality was lower among DT + patients (adjusted HR 0.6, 95%CI 0.4–0.7, p < 0.0001). However, ICD-unresponsive sudden deaths remained very rare and no more frequently observed among DT − patients (p = 0.41).
In our cohort, the higher (up to 40%) mortality at midterm among DT − patients is mainly reflecting their more severe cardiac disease, rather than a higher rate of ICD-unresponsive sudden death.