Optimizing the Programation of Cardiac Resynchronization Therapy Devices in Patients With Heart Failure and Left Bundle Branch Block

This study was conducted to investigate the clinical impact of cardiac resynchronization device optimization. A series of 100 consecutive patients received cardiac resynchronization therapy. In the first 49 patients, an empirical atrioventricular delay of 120 ms was set, with simultaneous biventricular stimulation (interventricular [VV] interval = 0 ms). In the next 51 patients, systematic atrioventricular optimization was performed. VV optimization was also performed, selecting 1 VV delay: right or left ventricular preactivation (+30 or −30 ms) or simultaneous (VV interval = 0 ms), according to the best synchrony obtained by tissue Doppler–derived wall displacement. At follow-up, patients who were alive without cardiac transplantation and showed improvement of ≥10% in the distance walked in the 6-minute walking test were considered responders. There were no differences between the 2 groups at baseline. Left ventricular ejection fraction improved in the 2 groups, but left ventricular cardiac output improved only in the optimized group. At 6 months, patients with optimized devices walked slightly further in the 6-minute walking test (497 ± 167 vs 393 ± 123 m, p <0.01), with no differences in New York Heart Association functional class or quality of life compared with nonoptimized patients. Overall, the number of nonresponders were similar in the 2 groups (27% vs 23%, p = NS). In conclusion, the echocardiographic optimization of cardiac resynchronization devices provided a slight incremental clinical benefit at midterm follow-up. Simple and rapid methods to routinely optimize the devices are warranted.