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Short Atrioventricular Mahaim Fibers: Observations on Their Clinical, Electrocardiographic, and Electrophysiologic Profile
Author(s) -
STERNICK EDUARDO BACK,
FAGUNDES MÁRCIO L.,
CRUZ FERNANDO E.S.,
TIMMERMANS CARL,
SOSA EDUARDO A.,
RODRIGUEZ LUZMARIA,
GERKEN LUIZ M.,
SCANAVACCA MAURÍCIO I.,
WELLENS HEIN J.J.
Publication year - 2005
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1046/j.1540-8167.2004.40508.x
Subject(s) - medicine , accessory pathway , cardiology , tachycardia , catheter ablation , ablation , radiofrequency catheter ablation , electrocardiography , atrioventricular reentrant tachycardia , radiofrequency ablation , electrical conduction system of the heart
A short atrioventricular decrementally conducting accessory pathway is an uncommon variant of preexcitation. Available data from small series suggest that their decremental properties might not be caused by A‐V nodal‐like tissue. Methods: We compared clinical, electrocardiographic and electrophysiologic parameters in two groups of patients: 8 patients with a short A‐V Mahaim pathway (Group A), and 33 patients with atriofascicular pathways (Group B). Radiofrequency catheter ablation was carried out guided by activation mapping at the annulus in Group A patients and targeting the “M” potential in Group B patients. Results: After ablation of all associated rapidly conducting bypass tracts, 7 of the 8 Group A patients showed clear preexcitation. In only 1 of 8 patients the short A‐V Mahaim fiber was actively engaged in a reentrant tachycardia circuit. During radiofrequency catheter ablation an automatic rhythm occurred in 4 of 8 patients. Intravenous adenosine caused conduction a block in the Mahaim fiber in 3 of the 5 patients tested. In group B, no patient showed clear preexcitation (P < 00001) while 72% had a minimal preexcitation pattern. Twenty‐nine of the 33 patients had a circus movement tachycardia with AV conduction over the atriofascicular fiber. During radiofrequency catheter ablation 30 of 33 patients showed accessory pathway automaticity. Adenosine caused transient block at the atriofascicular pathway in 11 (92%) of the 12 patients tested. Conclusions: While short decrementally conducting right‐sided accessory pathways show a typical ECG pattern different from atriofascicular pathways, their electrophysiologic properties do not seem to be uniform. Those pathways can be successfully interrupted by catheter ablation.