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Transverse dissociation of the human His bundle
Pacing and Clinical Electrophysiology : PACE
|May 1, 1982
Summary
Alternating Wenckebach periods, both completed and abortive, were observed in a patient with mitral annulus calcification. This rare arrhythmia stemmed from His bundle dissociation, necessitating pacemaker implantation.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Anatomy
Background:
- Wenckebach periods are a type of atrioventricular block characterized by a progressive lengthening of the PR interval followed by a dropped QRS complex.
- Transverse dissociation involves the splitting of cardiac conduction pathways, leading to complex arrhythmias.
- Mitral annulus calcification is a common finding that can be associated with cardiac arrhythmias.
Observation:
- A symptomatic female patient presented with alternating completed and abortive Wenckebach periods.
- These arrhythmias were linked to a unique anatomical finding: transverse dissociation of the His bundle into two distinct horizontal levels.
- A 2:1 block was identified in the distal level, while Wenckebach periods occurred in the proximal level of the His bundle.
Findings:
- The observed intra-Hisian alternating Wenckebach periods are rare and distinct from those originating in the atrioventricular node.
- This specific pattern of His bundle dissociation led to symptomatic arrhythmias.
- The condition required pacemaker implantation for management.
Implications:
- Intra-Hisian dissociation causing alternating Wenckebach periods is a rare but significant cause of symptomatic bradycardia.
- Understanding His bundle anatomy is crucial for diagnosing and managing complex conduction abnormalities.
- This case highlights the importance of differentiating His bundle dissociation from atrioventricular node dissociation for appropriate clinical management and treatment strategies.