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

Abstract

Background: Insufficient correction of mechanical dyssynchrony is a cause of non-response to cardiac resynchronization therapy (CRT).

Aims: To determine if CRT delivery could be optimized during the implantation procedure by choosing the number and location of pacing sites using echocardiography guidance.

Methods: 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.

Results: 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.

Conclusion: Intraoperative echocardiography-guided placement of RV lead(s) during CRT implantation is feasible and acutely improves LV synchrony compared with standard biventricular stimulation.

Keywords: Cardiac resynchronization therapy; Délai pré-éjectionnel gauche; Désynchronisation mécanique; Intraoperative echocardiography; Left pre-ejection interval; Mechanical dyssynchrony; Stimulation triple-site ventriculaire; Thérapie de resynchronisation cardiaque; Triple-site ventricular stimulation; Échocardiographie peropératoire.