Impact of segmental left ventricle lead position on cardiac resynchronization therapy outcomes.

BACKGROUND: The optimal pacing site for cardiac resynchronization therapy (CRT) is along the left ventricle (LV) lateral or posterolateral wall. However, little is known about the impact of segmental pacing site on outcomes.

OBJECTIVE: We assessed the impact of segmental LV lead position on CRT outcomes.

METHODS: Patients (n = 115) undergoing CRT were followed prospectively. Segmental LV lead position along the longitudinal axis (apical, midventricle, or basal) was determined retrospectively by examining coronary sinus (CS) venograms and chest X-rays. The primary outcome was a combined endpoint of heart failure hospitalization, cardiac transplantation, or all-cause mortality. Secondary outcomes included change in New York Heart Association (NYHA) functional class and degree of LV reverse remodeling.

RESULTS: Patients were divided into two groups based on LV lead position: apical (n = 25) and basal/midventricle (n = 90). The apical group was older (72.9 +/- 8.9 vs. 66.5 +/- 13.3 years; P = .010) and more likely to have ischemic cardiomyopathy (77% vs. 52%, P <.001). During a mean follow-up of 15.1 +/- 9.0 months, event-free survival was significantly lower in the apical group: 52% vs. 79%, hazard ratio [HR] 2.7 (95% confidence interval [CI] 1.5-5.5, P = .006). The adverse impact of apical lead placement remained significant after adjusting for clinical covariates: HR 2.3 (95% CI 1.1-4.8, P = .03). The apical group also experienced less improvement in NYHA functional class and less LV reverse remodeling.

CONCLUSIONS: Apical LV lead placement is associated with worse CRT outcomes. Preferential positioning of LV leads in the basal/midventricle segments may improve outcomes.