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Automaticity in Mahaim Fibers
Author(s) -
STERNICK EDUARDO BACK,
SOSA EDUARDO A.,
TIMMERMANS CARL,
FILHO FERNANDO E. CRUZ,
RODRIGUEZ LUZMARIA,
GERKEN LUIZ M.,
SCANAVACCA MAURÍCIO I.,
FAGUNDES MÁRCIO L.,
BUENO SÁVIA C.,
VRANDECIC MÁRIO O.,
WELLENS HEIN J.J.
Publication year - 2004
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.1540-8167.2004.03615.x
Subject(s) - antidromic , medicine , cardiology , automaticity , tachycardia , catheter ablation , anesthesia , ablation , electrophysiology , cognition , psychiatry
Automatic rhythms associated with Mahaim fibers usually occur during radiofrequency catheter ablation. The incidence and significance of spontaneous automaticity in Mahaim fibers are unknown. Methods and Results: Spontaneous automatic rhythms were observed in 5 (12.5%) of 40 patients with Mahaim fibers referred for nonpharmacologic therapy because of recurrent episodes of symptomatic tachyarrhythmias, usually antidromic circus movement tachycardia (33/40 patients). Three were female and two were male. Their mean age was 15 ± 7 years compared to 26 ± 13 years of the patients without automaticity (P = 0.09). Three patients had both antidromic tachycardia and asymptomatic spontaneous automatic rhythms recorded during ambulatory ECG (1 patient) or electrophysiologic study (2 patients). In 2 patients, the automatic rhythm triggered antidromic tachycardia. Two other patients had nonsustained repetitive episodes of wide QRS tachycardia due to automaticity arising in the Mahaim fiber, without antidromic tachycardia. All automatic rhythms were abolished by successful catheter ablation of the Mahaim fibers. Conclusion: Spontaneous automaticity occurred in 12.5% of our Mahaim patients and may trigger antidromic tachycardia. Spontaneous automaticity, which is not seen in rapidly conducting accessory pathways, is another argument for the presence of an AV nodal‐like structure in Mahaim fibers. (J Cardiovasc Electrophysiol, Vol. 15, pp. 738‐744, July 2004)