Deep septal pacing for pacemaker-induced cardiomyopathy

Abstract Background Conventional right ventricular pacing can impair left ventricular function and cause heart failure, known as pacing induced cardiomyopathy (PICM). Upgrade to cardiac resynchronization therapy (CRT) is the most common treatment for PICM. Recently, left bundle branch area pacing (LBBAP) has emerged as a potential alternative both to conventional RV pacing and to CRT. In Deep septal pacing (DSP), a simplified alternative to LBBAP, the lead is inserted deep in the septum, does not reach the subendocardial area, but is still able to achieve narrower paced QRS than during conventional pacing. Purpose The aim of this study was to assess the effect of DSP in a cohort of patients with PICM. Methods We included consecutive patients diagnosed with PICM who were referred to our unit between January 2020 and January 2022 for a device upgrade. The aim was to upgrade patients to DSP. In the absence of terminal R wave in V1, the procedure was considered successful if a paced QRS duration ≤140 ms was obtained. Clinical and device follow-up were performed one and 6 months after the procedure, and echocardiography at 6 months. The study was approved by the Clinical Research Ethics Committee and all patients signed informed consent. Results Fifteen patients were recruited during the study period. One patient was excluded because a QRS ≤ 140 ms could not be achieved, and 2 other patients because a terminal R wave in paced QRS in V1 was obtained. The characteristics of the 12 included cases are detailed in Table 1. The mean LVEF was 33% (SD 4%) and the mean percentage of RV pacing was 99% (SD 1%). All patients had symptomatic heart failure. Non stylet-driven electrodes were used in 8 of the 12 patients. Acute threshold was < 1V - 0’4 ms in all, and remained stable during follow-up. No procedure-related complications or lead dislodgements were detected. The mean paced QRS duration with RV pacing was 172 ms (SD 14 ms) whereas after the upgrade it was 130 ms (SD 7 ms). As compared to RV pacing, DSP was associated with a significant reduction in paced QRS duration (mean difference 41 ms, p<0.001). As shown in Table 1, after DSP all patients except one (11/12, 92%) experienced an increase in LVEF of at least 10%; five patients (42%) achieved an LVEF>50%. The mean LVEF after the upgrade was 46% (SD 9%). The mean improvement in LVEF with DSP was 13% (SD 10%). Conclusions In patients with PICM, deep septal pacing achieves narrower QRS as compared to RV pacing and is associated with a significant improvement in LVEF. Deep septal pacing might be an effective and simpler alternative to biventricular or left bundle branch pacing in patients with PICM.Table 1