The effectiveness of CRT on improvement of survival of heart failure patients in real life clinical settings.

Objectives Prolongation of QRS (≥ 120 ms) in patients with heart failure (HF) is associated with higher all-cause mortality than in those with narrow QRS. The aim of our study was to compare the survival of patients with HF and wide QRS after cardiac resynchronization therapy (CRT) with survival of HF patients with narrow QRS and to assess factors predictive of non-response to CRT. Methods We enrolled 680 patients with advanced HF and optimal pharmacologic therapy. All patients were assigned according to duration of QRS complex and implanted device. We acquired two groups. A first group, patients with wide QRS and implanted CRT-D (CRT-D group, n = 354) and a second group, patients having narrow QRS and implanted single/dual chamber ICD (ICD group, n = 326). The primary outcome was death from any cause. The response to CRT was defined as an increase of EF at least by 5% and/or reduction of LVEDD at least by 10%. Results The primary outcome was reached by 84 (23.7%) patients in the CRT-D group and 69 (21.2%) patients in the ICD group. We did not find a statistically significant difference in survival rate between the CRT-D and ICD group [P = 0.44; hazard ratio (HR) 1.132]. Conclusion Survival of patients with HF and wide QRS after CRT implantation is comparable to those with HF and narrow QRS. Coronary artery disease and QRS width less than 145 ms increase risk of non-response to CRT 2.2 and 2.9 times, respectively.