His bundle recordings in diagnosis of impulse formation in Kent and Mahaim tracts

Agustin Castellanos, Ruey J. Sung, Cesar A. Castillo, Abdul S. Agha, Benjamin Befeler, Robert J. Myerburg

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


His bundle electrograms were recorded in 2 patients with ectopic beats arising in accessory atrioventricular tracts. Case 1 had Wolff-Parkinson-White (WPW) type A and a left-sided Kent tract with a short effective refractory period. Though ectopic impulse formation most probably occurred within the Kent tract itself, a vulnerability-related origin in the ventricular muscle close to the distal end of the Kent tract could not be excluded. In Case 2, with a Mahaim tract extending from His bundle to ventricles, there were three types of QRS morphologies resulting from: (a) atrioventricular conduction exclusively through the normal pathway; (b) atrioventricular conduction through both, normal pathway, and Mahaim tract; and (c) ectopic impulse formation in the Mahaim tract. Specialized electrophysiological studies were essential to diagnose these unusual arrhythmias.

Original languageEnglish (US)
Pages (from-to)1173-1178
Number of pages6
Issue number11
StatePublished - 1976

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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