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Dual conduction in a Mahaim fiber
Eduardo Back Sternick1, Eduardo A Sosa, Maurício I Scanavacca
1Department of Arrhythmia and Electrophysiology of BIOCOR Instituto, Nova Lima, Brazil. eduardosternick@aol.com
Journal of Cardiovascular Electrophysiology
|October 16, 2004
Summary
An 8-year-old girl with drug-resistant tachycardia was successfully treated by catheter ablation. The study identified a rare accessory pathway involving Mahaim fibers as the cause of her arrhythmia.
Area of Science:
- Cardiology
- Electrophysiology
- Pediatric Arrhythmia
Background:
- Nonsustained tachycardia can be challenging to manage, especially in pediatric patients.
- Accessory pathways, such as Mahaim fibers, can cause complex cardiac arrhythmias.
- Antiarrhythmic drug therapy is not always effective for certain types of tachycardia.
Observation:
- An 8-year-old girl presented with incessant, drug-refractory left bundle branch block-like tachycardia.
- Electrophysiologic study identified a right-sided accessory atriofascicular pathway (Mahaim fiber).
- Tachycardia episodes were linked to dual atrioventricular conduction over the Mahaim fiber to a single P wave, without reentrant circuits.
Findings:
- Catheter ablation targeting a Mahaim potential at the right lateral tricuspid annulus successfully eliminated the arrhythmia.
- The mechanism may involve longitudinal dissociation within a single Mahaim fiber or dual Mahaim fibers with differing conduction properties.
Implications:
- Catheter ablation is a viable curative option for Mahaim fiber-related tachycardia in children.
- Understanding Mahaim fiber physiology is crucial for diagnosing and treating complex pediatric arrhythmias.
- This case highlights the importance of detailed electrophysiologic study for identifying uncommon arrhythmia substrates.