Repolarization changes following left bundle branch area pacing versus conventional biventricular pacing in patients with dyssynchronous heart failure

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Dutch Heart Foundation. Background Biventricular pacing (BiVP) is the standard treatment for patients with dyssynchronous heart failure. Despite the effectiveness of BiVP, 6% of patients develop ventricular tachyarrhythmia’s (VTAs) within one year following implantation. The relationship between BiVP and the development of VTAs is still under debate. The left-sided epicardium-to-endocardium activation during BiVP creates a nonphysiological activation and repolarization and might provoke VTAs. A relatively new treatment option is left bundle branch area pacing (LBBAP), in which the physiological activation of the left ventricle is restored. We hypothesize that LBBAP leads to a more homogenous repolarization compared to conventional BiVP. Purpose To compare time-dependent repolarization changes in patients with dyssynchronous heart failure receiving LBBAP versus BiVP. Methods Patients with dyssynchronous heart failure eligible for cardiac resynchronization therapy who underwent LBBAP (n=13) or BiVP (n=28) were retrospectively included. Standard 12-lead electrocardiograms (ECG) obtained prior to implantation [baseline], shortly following implantation (0-2 days,[acute]) and during follow-up (31-180 days, [FU]) were analyzed. The QT interval and Tpeak to Tend interval (Tpeak-Tend) were calculated using a semi-automatic approach in MATLAB. Repolarization differences between LBBAP and BiVP patients were determined using the Mann-Whitney U-test. Time-dependent changes within groups were determined using the Wilcoxon signed rank tests. Significance was defined as a p-value ≤0.05. Results The QT interval did not significantly change over time in BiVP patients, but it decreased immediately following implantation and during FU in LBBAP patients. At FU, QT interval was significantly lower in LBBAP than in BiVP patients (Figure 1, left panel). A slight increase in Tpeak-Tend interval over time in BiVP patients, while it tends to decrease over time in LBBAP patients can be seen in the right panel. Acutely and long term after implantation, Tpeak-Tend was significantly lower in LBBAP than in BiVP patients. Conclusion LBBAP is associated with lower QT and Tpeak-Tend intervals compared to BiVP during FU, suggesting that LBBAP leads to less heterogeneity of repolarization over time. These findings suggest a more physiological repolarization pattern in LBBAP compared to BiVP, which may decrease the risk of developing VTAs.