Left Ventricular Lead Position and Nonspecific Conduction Delay Are Predictors of Mortality in Patients During Cardiac Resynchronization Therapy

Background: Cardiac resynchronization therapy (CRT) is an established treatment of severe systolic heart failure with intraventricular conduction delay. The influence on mortality of the left ventricular (LV) pacing site and the type of bundle-branch block during CRT is unclear. Objectives: This study investigates the clinical significance of LV lead position, as well as nonspecific conduction delay, in CRT. Methods: 143 consecutive patients (mean age, 63.9 +/- 8.9 years; 121 men) underwent implantation of a CRT device according to established criteria. At the time of implantation, the LV lead position and the type of bundle-branch block were recorded. The etiology of the heart failure was ischemic in 49 patients (34.3%) and nonischemic in 94 patients (65.7%). Results: After a median follow-up of 19 months, 39 patients (27.3%) died, most of them (72%) of cardiovascular causes. The mortality was significantly higher in patients with an anterior or anterolateral LV lead position (P = 0.03). Multivariate analysis suggests that an anterior or anterolateral LV lead position, a nonspecific conduction delay, male sex, and a New York Heart Association functional class worse than III, are all independent predictors of mortality during the follow-up period. Conclusion: LV lead position and nonspecific conduction delay are predictors of mortality in patients during cardiac resynchronization therapy.