Wenckebach pattern in right bundle branch block - benign or not?
Weiting Huang1, Paul Chun Yih Lim1, Chi-Keong Ching1
1National Heart Centre of Singapore, Singapore.
Journal of Electrocardiology
|March 26, 2017
Summary
Mobitz type I block with a wide QRS complex on ECG may indicate infra-Hisian conduction abnormalities, not just AV nodal disease. This finding suggests potential His-Purkinje system involvement in Wenckebach block.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Diagnostics
Background:
- Mobitz type I block (Wenckebach phenomenon) typically involves the AV node when associated with a narrow QRS complex.
- Wide QRS complexes (>0.12sec) in Mobitz type I block suggest potential His-Purkinje system involvement.
Observation:
- Progressive PR prolongation with conducted beats indicates Wenckebach phenomenon.
- The accompanying QRS complex width is crucial for localization.
- Axis changes in persistent right bundle branch block may suggest alternating fascicular block and unreliable infra-Hisian conduction.
Findings:
- Wide QRS Mobitz type I block occurs in the His-Purkinje system in 60-70% of cases.
- Infra-Hisian Wenckebach block is rare, with limited literature.
- This case report highlights wide QRS Wenckebach block as a potential indicator of infra-Hisian conduction abnormalities.
Implications:
- Recognizing wide QRS Wenckebach block is vital for accurate diagnosis and localization of conduction system disease.
- In symptomatic patients with suspected infra-Hisian block, pacemaker implantation may be indicated.
- Further research into infra-Hisian conduction abnormalities is warranted.
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