Invasive Optimization of Cardiac Resynchronization Therapy: Role of Sequential Biventricular and Left Ventricular Pacing

Abstract

Background: Aim of this invasive study was to characterize and quantify changes in left ventricular (LV) systolic function due to sequential biventricular pacing (BV) as compared to right atrial triggered simultaneous BV (BV₀), LV, and right ventricular (RV) pacing in patients with congestive heart failure (CHF). Methods: In 22 CHF patients, all in sinus rhythm, temporary multisite pacing was performed prior to implantation of a permanent system. LV systolic function was evaluated invasively by the maximum rate of LV pressure increase (dP/dt_max). Sequential BV pacing was performed with preactivation of either ventricle at 20–80 ms. Results: In comparison to RV pacing, LV and BV₀ pacing increased dP/dt_max by 33.9 ± 19.3% and 34.0 ± 22.6%, respectively (P < 0.001). In 9 patients, optimized sequential BV pacing further improved dP/dt_max by 8.5 ± 4.8% compared to BV₀ (range 3.3–17.1, P < 0.05). In 10 patients exhibiting a PR interval ≤200 ms, LV pacing was either superior (n = 6) or equal to BV₀ pacing (n = 4). In these 10 patients, LV pacing yielded a 7.4 ± 8.0% higher dP/dt_max than BV₀ pacing (P < 0.05). Conclusions: Using sequential BV pacing, generally with LV preactivation, moderate improvements in LV systolic function can be achieved in selected patients. Baseline PR interval may aid in the selection of the optimum cardiac resynchronization therapy (CRT) mode, favoring LV pacing in patients with a PR interval ≤200 ms.