First experience of intraoperative echocardiography-guided optimization of cardiac resynchronization therapy delivery

Abstract

Insufficient correction of mechanical dyssynchrony is a cause of non-response to cardiac resynchronization therapy (CRT). To determine if CRT delivery could be optimized during the implantation procedure by choosing the number and location of pacing sites using echocardiography guidance. In patients with a QRS ≥ 150 ms or a QRS < 150 ms and criteria for mechanical dyssynchrony, the objective of the implantation procedure was to shorten the left pre-ejection interval (LPEI), measured online, by at least 10 ms compared with standard biventricular configuration, by moving the right ventricular (RV) lead at different locations and, if necessary, by adding a second RV lead. Ninety-one patients (70 men; mean age 73 ± 10 years; left ventricular [LV] ejection fraction 29 ± 10%) were included. The final pacing configuration was standard biventricular in 15 (17%) patients, optimized biventricular in 22 (24%) and triple-site ventricular in 54 (59%). LPEI was shortened by ≥ 10 ms compared with standard biventricular stimulation in 73 (80%) patients. Compared with standard biventricular pacing, the final optimized pacing configuration improved global intraventricular synchrony (decreasing LPEI from 158 ± 36 ms to 134 ± 29 ms; P<0.001), LV systolic efficiency (decreasing LPEI/LV ejection time from 0.58 ± 0.18 to 0.46 ± 0.13; P<0.001) and LV filling (increasing LV filling time/RR from 44 ± 8% to 47 ± 7%; P<0.001) and decreased mitral valve regurgitation. Intraoperative echocardiography-guided placement of RV lead(s) during CRT implantation is feasible and acutely improves LV synchrony compared with standard biventricular stimulation.