Left bundle branch pacing with and without anodal capture: impact on ventricular activation pattern and acute
Nadine Ali1, Khulat Saqi1, Ahran D Arnold1
1National Heart and Lung Institute-Cardiovascular Science, The Hammersmith Hospital, Imperial College London, B-Block South, 2nd Floor, Du Cane Road, London W12 0NN, UK.
Insights
Anodal capture during left bundle branch pacing (LBBP) advances right ventricular (RV) activation by stimulating the RV septum. However, this method requires higher energy outputs without providing significant hemodynamic benefits.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Left bundle branch pacing (LBBP) offers physiological left ventricular activation.
- LBBP can lead to delayed right ventricular (RV) activation.
- Anodal capture is a technique to potentially advance RV activation during LBBP.
Purpose of the Study:
- To investigate the mechanism of advanced RV activation during LBBP with anodal capture.
- To determine if anodal capture provides hemodynamic benefits.
- To assess the clinical necessity of aiming for anodal capture in LBBP.
Main Methods:
- Recruited 21 patients with LBBP leads exhibiting anodal capture.
- Studied ventricular activation patterns and timing using electrocardiography and non-invasive mapping.
- Measured acute hemodynamic response during LBBP with and without anodal capture.
Main Results:
- Anodal capture advanced RV activation by stimulating the RV septal myocardium, not the right bundle.
- QRS duration and total ventricular activation times were significantly shorter with anodal capture.
- Higher pacing outputs were required for anodal capture, with no significant improvement in acute hemodynamics.
Conclusions:
- Anodal capture during LBBP advances RV activation via RV septal myocardial stimulation.
- This technique necessitates higher energy outputs.
- Anodal capture does not improve acute hemodynamic performance, suggesting it may not be a necessary target in LBBP.
Aims:
Left bundle branch pacing (LBBP) can deliver physiological left ventricular activation, but typically at the cost of delayed right ventricular (RV) activation. Right ventricular activation can be advanced through anodal capture, but there is uncertainty regarding the mechanism by which this is achieved, and it is not known whether this produces haemodynamic benefit.
Methods And Results:
We recruited patients with LBBP leads in whom anodal capture eliminated the terminal R-wave in lead V1. Ventricular activation pattern, timing, and high-precision acute haemodynamic response were studied during LBBP with and without anodal capture. We recruited 21 patients with a mean age of 67 years, of whom 14 were males. We measured electrocardiogram timings and haemodynamics in all patients, and in 16, we also performed non-invasive mapping. Ventricular epicardial propagation maps demonstrated that RV septal myocardial capture, rather than right bundle capture, was the mechanism for earlier RV activation. With anodal capture, QRS duration and total ventricular activation times were shorter (116 ± 12 vs. 129 ± 14 ms, P < 0.01 and 83 ± 18 vs. 90 ± 15 ms, P = 0.01). This required higher outputs (3.6 ± 1.9 vs. 0.6 ± 0.2 V, P < 0.01) but without additional haemodynamic benefit (mean difference -0.2 ± 3.8 mmHg compared with pacing without anodal capture, P = 0.2).
Conclusion:
Left bundle branch pacing with anodal capture advances RV activation by stimulating the RV septal myocardium. However, this requires higher outputs and does not improve acute haemodynamics. Aiming for anodal capture may therefore not be necessary.
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