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Updated: Jun 4, 2026
12:45
Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
A His bundle extrasystole can both induce and reverse 2:1 atrioventricular block
Abdullah Khan1, Abdul Ameen, Ilir Maraj
1Downstate Medical Center and New York Harbor VA Healthcare Center, State University of New York, Brooklyn, NY, USA.
Summary
A novel His bundle extrasystole (H) manifestation caused atrioventricular block in an elderly man. Procainamide suppressed these extrasystoles, but a pacemaker was ultimately required due to persistent symptoms.
Area of Science:
- Cardiology
- Electrophysiology
- Clinical Medicine
Background:
- Recurrent dizziness in an 84-year-old man was investigated.
- The patient presented with a history of first-degree atrioventricular block (1° AVB) and intermittent 2:1 AVB.
Observation:
- Electrophysiological study revealed dominant 1:1 atrioventricular (AV) conduction with a prolonged AH interval.
- Frequent His bundle extrasystoles (H) were observed.
- These His bundle extrasystoles were found to induce periods of 2:1 AV nodal block.
Findings:
- Properly timed His bundle extrasystoles could trigger 2:1 AV nodal block.
- 1:1 AV conduction only resumed after a subsequent correctly timed His bundle extrasystole.
- Procainamide administration successfully suppressed the His bundle extrasystoles.
- Despite pharmacological intervention, the patient's symptoms persisted.
Implications:
- This case describes a previously unrecognized manifestation of His bundle extrasystoles.
- The findings highlight a complex interplay between His bundle activity and AV conduction.
- The necessity for a permanent pacemaker underscores the clinical significance of this phenomenon.
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