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[Improvement and normalisation of the QRS complex by stimulation of the bundle of His in complete left branch block]
Insights
Stimulating the His Bundle can correct asynchronous ventricular activation in patients with left bundle branch block. This His Bundle stimulation normalizes ventricular depolarization, improving heart rhythm.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Conduction System
Context:
- Left bundle branch block (LBBB) causes significant delays in ventricular activation, leading to asynchronous depolarization.
- This asynchrony can impair cardiac function and is often associated with a QRS duration ≥ 0.12 seconds.
Purpose:
- To investigate the effect of His Bundle stimulation on ventricular activation in patients with LBBB.
- To determine if His Bundle stimulation can normalize or improve ventricular depolarization patterns.
Summary:
- Stimulation of the distal His Bundle effectively suppressed asynchronous ventricular activation in both intermittent and permanent left bundle branch block.
- Selective His Bundle stimulation normalized ventricular depolarization, while non-selective stimulation narrowed the QRS complex through wave front fusion.
- The findings suggest longitudinal dissociation within the His Bundle or a localized lesion at the left bundle origin.
Impact:
- His Bundle stimulation offers a potential therapeutic strategy to restore synchronous ventricular conduction in LBBB.
- Understanding the electrophysiological mechanisms can refine diagnostic and therapeutic approaches for conduction system diseases.
- This research contributes to the understanding of cardiac electrophysiology and the management of complex arrhythmias.
Abstract:
The asynchronism of ventricular activation resulting from a major degree of left bundle branch block (QRS greater than or equal to 0.12 s) may be suppressed by stimulation of the distal portion of the His Bundle, whether the block be intermittent (3 cases) or permanent (17 cases). The selective stimulation of the His Bundle normalises ventricular depolarisation whilst non-selective stimulation narrows the QRS complex by the fusion of the activation wave fronts from the His Bundle and the interventricular septum. The reestablishment of synchronous ventricular conduction by His Bundle stimulation is generally interpreted as a sign of longitudinal dissociation in the proximal portion of the His Bundle. This results does not, however, exclude the possibility of a very localised lesion at the origin of the left bundle, responsible for a conduction delay, and suppressed by stimulation carried out close to the zone of block (summation effect, electrotonic influence).