Effect of leadless left ventricular endocardial and left bundle branch area pacing on biventricular repolarization
Nadeev Wijesuriya1, Marina Strocchi2, Mark Elliott2
1Department of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom; Department of Cardiovascular Medicine, Guy's and St Thomas's NHS Foundation Trust, London, United Kingdom.
Insights
Leadless cardiac resynchronization therapy (CRT) using endocardial pacing or left bundle branch area pacing (LBBAP) improves ventricular repolarization. LV-only pacing demonstrated superior results compared to biventricular pacing.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Imaging
Background:
- Cardiac resynchronization therapy (CRT) with epicardial pacing can increase arrhythmic risk due to adverse effects on ventricular repolarization.
- Leadless LV endocardial CRT, including leadless left bundle branch area pacing (LBBAP), may reduce this risk by promoting physiological transmural activation.
Purpose of the Study:
- To evaluate the impact of leadless LV endocardial pacing and leadless LBBAP on repolarization metrics using electrocardiographic imaging (ECGi).
Main Methods:
- Ten patients with leadless endocardial CRT systems underwent ECGi studies with various pacing settings (RV, LV, BiVP, AV-optimized LV).
- Epicardial electrograms were analyzed to derive repolarization and activation-recovery interval dispersion metrics.
- Primary outcome was acute reduction in repolarization metrics from baseline.
Main Results:
- Optimal leadless pacing significantly improved biventricular repolarization dispersion by 23.7% (P < .01), with LBBAP showing a more pronounced effect (29.3%) than lateral wall pacing (18%).
- Similar improvements were noted for activation-recovery interval dispersion and repolarization gradients.
- LV-only pacing (LBBAP or AV-optimized LV) yielded greater improvements than biventricular pacing (BiVP).
Conclusions:
- Optimized leadless LV endocardial pacing and LBBAP enhance ECGi-derived ventricular repolarization.
- LV-only pacing appears superior to endocardial BiVP, potentially due to avoiding repolarization heterogeneity from colliding paced wavefronts.
Background:
Cardiac resynchronization therapy (CRT) delivered with left ventricular (LV) epicardial pacing may increase arrhythmic risk through detrimental effects on ventricular repolarization. Leadless LV endocardial CRT including leadless left bundle branch area pacing (LBBAP) may mitigate this by preserving a more physiological transmural activation pattern.
Objective:
This study aimed to evaluate the effect of leadless LV endocardial and leadless LBBAP on repolarization metrics derived from electrocardiographic imaging (ECGi).
Methods:
Ten patients with leadless endocardial CRT systems underwent a temporary pacing plus ECGi study, testing right ventricular, LV, and biventricular pacing (BiVP) settings, as well as atrioventricular-optimized LV pacing. Epicardial electrograms were used to derive metrics of repolarization and activation-recovery interval dispersion. The primary outcome measurements were acute improvement (ie, reduction) from baseline (right ventricular pacing or underlying rhythm) of these repolarization metrics.
Results:
Ten patients were studied; 5 had received LV lateral wall endocardial pacing, and 5 had received LBBAP with leadless septal wall pacing. The optimal leadless pacing setting significantly improved biventricular dispersion of repolarization by 23.7% ± 14% (P < .01), and this effect was more pronounced with LBBAP (29.3% ± 15%, P = .01) vs lateral wall pacing (18% ± 12%, P = .03). Similar results were observed for activation-recovery interval dispersion and biventricular repolarization gradients. The most pronounced improvements were observed where LV-only pacing as opposed to BiVP was used, either through LBBAP or atrioventricular-optimized LV pacing from any endocardial location.
Conclusion:
Optimized leadless LV endocardial lateral wall pacing and LBBAP improve ECGi-derived ventricular repolarization metrics. LV-only pacing seemed superior to endocardial BiVP, potentially reflecting repolarization heterogeneity caused by a collision of 2 paced wavefronts.
