His bundle lead placement: Is His bundle captured?
Ronpichai Chokesuwattanaskul1, Krit Jongnarangsin1
1Division of Cardiac Electrophysiology, University of Michigan Health Care, Ann Arbor, Michigan.
Insights
This study explores His bundle pacing in a patient with heart block. Analysis of intracardiac electrograms suggests His bundle capture may not have occurred, highlighting the complexity of pacing technologies.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- A 59-year-old female received a dual-chamber pacemaker for intermittent complete heart block.
- Baseline electrocardiogram revealed normal sinus rhythm with first-degree atrioventricular (AV) block and right bundle branch block.
Observation:
- A His bundle lead was implanted, and intracardiac electrograms showed atrial-His and His-ventricular intervals of 186 ms and 110 ms, respectively.
- Pacing from the His bundle lead with decreasing output did not result in significant QRS morphology changes.
Findings:
- The study questions whether His bundle capture was achieved despite lead placement.
- Intracardiac electrogram analysis revealed specific conduction intervals within the His Purkinje system.
Implications:
- Understanding His Purkinje system physiology is crucial for advanced pacing techniques.
- This case highlights the challenges and diagnostic considerations in His bundle pacing and conducting system pacing technologies.
Abstract:
A 59-year-old female underwent a dual-chamber pacemaker implantation for intermittent complete heart block. A baseline electrocardiogram showed normal sinus rhythm with first-degree atrioventricular (AV) block and right bundle branch block. A His bundle lead placement was attempted. An intracardiac electrogram from the His bundle lead demonstrated atrial-His, and His-ventricular intervals were 186 and 110 ms, respectively. Pacing was performed from the His bundle lead with a decremental pacing output to assess for the His bundle capture threshold. However, there were no significant QRS morphology changes during the pacing. Is the His bundle captured? The tracing evaluation demonstrated the fascinating physiology of activation wavefront in His Purkinje system that could be applied in the use of conducting system pacing technologies.
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