This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ormaetxe, J. M. Articles by Delcan, J. L. Search for Related Content PubMed PubMed Citation Articles by Ormaetxe, J. M. Articles by Delcan, J. L.

Circulation, Vol 88, 2623-2631, Copyright © 1993 by American Heart Association

ARTICLES

Ventricular fusion during resetting and entrainment of orthodromic supraventricular tachycardia involving septal accessory pathways. Implications for the differential diagnosis with atrioventricular nodal reentry

JM Ormaetxe, J Almendral, A Arenal, JD Martinez-Alday, A Pastor, JP Villacastin and JL Delcan
Clinical Electrophysiology Laboratory, Hospital General Gregorio Maraon, Madrid, Spain.

BACKGROUND. Ventricular fusion during transient entrainment of orthodromic atrioventricular reciprocating tachycardias (OAVRT) was originally found to be absent and recently observed only with left ventricular stimulation. However, previous studies were restricted to cases with a left free wall accessory pathway. The hypothesis of the present study was that fusion is likely during resetting and entrainment of OAVRT with right ventricular stimulation if the accessory pathway is septally located, since its insertion is relatively close to the stimulation site. This phenomenon can help in the differential diagnosis with atrioventricular nodal reentry (AVNR). METHODS AND RESULTS. We performed programmed right ventricular stimulation during regular inducible supraventricular tachycardia with concentric atrial activation in 44 patients--20 with OAVRT and 24 with AVNR. Fusion in the ECG morphology of extrastimuli producing resetting was observed in 19 of 19 OAVRT but in 0 of 11 AVNR reset (P < .001). Transient entrainment was demonstrated in all 31 cases undergoing rapid ventricular pacing (14 OAVRT and 17 AVNR). Entrainment with fusion occurred in 13 of 14 OAVRT and in 0 of 17 AVNR (P < .001). Fusion was critically dependent on the coupling intervals or pacing rates, sometimes having a narrow window for its observation. CONCLUSIONS. The relative proximity (conduction time) among pacing site, site of entrance to a reentrant circuit, and site of exit from the circuit to the paced chamber are critical for the occurrence of fusion during resetting and/or entrainment. The presence or absence of fusion during these phenomena can help in the differential diagnosis of certain supraventricular tachycardias.

This article has been cited by other articles:

				J. Perez-Rodon, V. Bazan, J. Bruguera-Cortada, S. Mojal-Garcia, J. M. Manresa-Dominguez, and J. Marti-Almor Entrainment from the para-Hisian region for differentiating atrioventricular node reentrant tachycardia from orthodromic atrioventricular reentrant tachycardia Europace, October 1, 2008; 10(10): 1205 - 1211. [Abstract] [Full Text] [PDF]

				D. G Katritsis and A. J. Camm Classification and differential diagnosis of atrioventricular nodal re-entrant tachycardia. Europace, January 1, 2006; 8(1): 29 - 36. [Abstract] [Full Text] [PDF]

				G. F. Michaud, H. Tada, S. Chough, R. Baker, K. Wasmer, C. Sticherling, H. Oral, F. Pelosi Jr, B. P. Knight, S. A. Strickberger, et al. Differentiation of atypical atrioventricular node re-entrant tachycardia from orthodromic reciprocating tachycardia using a septal accessory pathway by the response to ventricular pacing J. Am. Coll. Cardiol., October 1, 2001; 38(4): 1163 - 1167. [Abstract] [Full Text] [PDF]

				J. L. Merino, R. Peinado, I. Fernandez-Lozano, N. Sobrino, and J. A. Sobrino Transient Entrainment of Bundle-Branch Reentry by Atrial and Ventricular Stimulation : Elucidation of the Tachycardia Mechanism Through Analysis of the Surface ECG Circulation, October 26, 1999; 100(17): 1784 - 1790. [Abstract] [Full Text] [PDF]

				J. L. Merino, J. R. Carmona, I. Fernandez-Lozano, R. Peinado, N. Basterra, and J. A. Sobrino Mechanisms of Sustained Ventricular Tachycardia in Myotonic Dystrophy : Implications for Catheter Ablation Circulation, August 11, 1998; 98(6): 541 - 546. [Abstract] [Full Text] [PDF]

				J. M. Ormaetxe, J. Almendral, J. D. Martinez-Alday, J. P. Villacastin, A. Arenal, A. Pastor, T. Echeverria, and J. L. Delcan Analysis of the Degree of QRS Fusion Necessary for Its Visual Detection : Importance for the Recognition of Transient Entrainment Circulation, November 18, 1997; 96(10): 3509 - 3516. [Abstract] [Full Text]