Conduction system pacing to preserve ventricular function after cardiac surgery: a comparison with conventional right ventricular pacing

Background permanent pacemaker implantation (PPi) is frequently needed after cardiac surgery (CS), especially after valve surgery. Right ventricular pacing (RVP) may induce ventricular dyssynchrony and long-term reduction of left ventricular ejection fraction (LVEF); conversely, conduction system pacing (CSP) provides physiological electrical activation and preserves LVEF in many clinical settings. Purpose aim of our study was to compare CSP and RVP in patients with normal baseline LVEF, needing PPi after CS. Methods all patients undergoing PPi because of atrioventricular block after CS were prospectively enrolled across five centers. Patients with a ventricular pacing burden <40% were excluded. Clinical and echocardiographic evaluations were performed at baseline and 6 months after PPi. Results 202 patients were enrolled: 117 underwent RVP implantation and 85 underwent CSP implantation. Recipients of RVP had a lower EF at follow-up compared with CSP recipients (RVP EF: 52.2±4.7% vs CSP EF: 56.95±2%; p<0.001). The ΔEF was –3.1 ± 4.8% in the RVP group versus +0.4 ± 4.0% in the CSP group (p<0.0001), as shown in Picture 1. Among RVP patients, 24.6% experienced LVEF reduction >5%, and 22% had LVEF <52% at follow-up. Paced QRS duration was significantly shorter in CSP recipients (RVP: 138.1±16.7 ms; CSP: 115.4±17.7 ms; p<0.001). Discussion: RVP after CS was associated with early systolic deterioration, whereas CSP preserved LVEF, probably thanks to a more physiological depolarization of the ventricles, testified by shorter QRS interval. Conclusion CSP seems protective against pacing-induced LVEF reduction in post-CS PPi and may be preferable compared to RVP also in patients with preserved LVEF.