Comparison of Upgrading to Conduction System Pacing and Biventricular Pacing in Patients with Pacemaker-induced Cardiomyopathy

Abstract Background: Pacemaker-induced cardiomyopathy (PICM) is common in patients with right ventricular pacing (RVP). We are still not clear whether the conduction system pacing (CSP) upgrade is better than the traditional biventricular pacing (BiVP) upgrade. Objective: To illustrate the performances of different upgrade modalities in patients with PICM. Methods: All patients with PICM were consecutively enrolled and followed for at least one year regardless of resynchronization upgrade from 2017 to 2021. Clinical data, including echocardiographic parameters, electrocardiogram measurements and cardiac function, were collected and compared. Results: A total of 73 patients were enrolled. Forty-eight patients had a resynchronization upgrade including 11 patients with BiVP, 24 patients with HBP and 13 patients with LBBP. The QRS duration (127.81±31.89 vs. 177.08±34.35ms, P <0.001), NYHA class (2.28±0.70 vs. 3.04±0.54, P <0.05), left ventricular end-diastolic diameter (LVEDD) (54.08±4.80 vs. 57.50±4.85mm, P <0.05) and LVEF (44.46±6.39 vs. 33.15±5.25%, P <0.001) improved significantly in patients with upgrade, while no improvement was detected in patients without upgrade. The range of improvement in QRS duration (59.65±11.71 vs. 34.67±13.32ms, P <0.001), LVEDD (5.80±1.71 vs. 3.16±1.35mm, P <0.001), LVEF (12.80±3.66 vs. 6.93±3.04%, P <0.001) were more significant in patients with CSP compared with BiVP. However, the range of improvement of LVEDD and LVEF were not different between LBBP and HBP. The threshold in LBBP was lower than HBP (1.01±0.43 vs. 1.33±0.32V, P =0.019). Conclusion: The improvement of clinical outcomes in CSP were more significant than in BiVP. CSP may be an alternative therapy of CRT in patients with PICM. LBBP would be a better choice for achieving lower thresholds compared with HBP.