Abstract 17174: Comparison of the Mechanism and Anatomical Tachycardia Circuit between the Verapamil-Sensitive Atrial Tachycardia Originating from the Vicinity of the Atrioventricular Node and from the Non-vicinity Area along the Atrioventricular Annulus
Background: Little is known about the difference in the mechanism and the anatomical tachycardia circuit between the verapamil-sensitive focal atrial tachycardia (AT) originating from the vicinity of the atrioventricular node (AVN-AT) and the AT originating from the AV annulus other than the AV node vicinity (AVA-AT).
Objectives: We clarified the electrophysiologic mechanism and tachycardia circuit of the AVN-AT and the AVA-AT and elucidated its difference.
Methods: Seventeen AVN-AT patients and 23 AVA-AT patients were included. While recording the atrial electrogram at the earliest activation site (EAAS), rapid atrial pacing at a rate 5 beats/minute faster than the tachycardia rate was delivered from multiple atrial sites during AT to demonstrate manifest entrainment and orthodromic capture of EAAS. Manifest entrainment pacing site was defined as the site located proximal to the slow conduction area of reentry circuit. Radiofrequency energy was delivered starting at a site 2 cm proximal to the EAAS in the direction of entrainment pacing site. Then the application site was gradually advanced toward the EAAS until termination of AT to define the entrance of the slow conduction area of the reentry circuit.
Results: Manifest entrainment associated with the orthodromic capture of the EAAS was demonstrated in all patients both in AVN-AT and AVA-AT. Radiofrequency energy delivery to a site proximal to the EAAS terminated all ATs. There was no significant difference in the tachycardia cycle length (429.2±76.5 vs. 431.2±93.9 msec, p=NS), distance between the successful ablation site and the EAAS (10.1±7.8 vs. 10.4±2.4 mm, p=NS), activation time from the EAAS to successful ablation site (16.4±6.5 vs. 13.9±5.7 msec, p=NS) and interval from the onset of radiofrequency energy delivery to the termination of AT (2.9±1.1 vs. 2.9±0.9 msec, p=NS) between AVN-AT and AVA-ATs.
Conclusions: The AVN-AT and AVA-AT are both organized as reentry involving the verapamil-sensitive slow conduction area with its entrance and exit at different distinct locations. The verapamil-sensitive AT arises not only from the vicinity of the AV node but also along the AV annulus with common electrophysiologic mechanism and anatomical tachycardia circuit.
Author Disclosures: H. Yamabe: Other Research Support; Modest; Medtronic Japan, Nihon Kohden, Boston scientific, St Jude Medical, Japan Lifeline, Fukuda Denshi, Neotec Japan, Shionogi. H. Kanazawa: None. T. Hoshiyama: None. M. Ito: None. H. Ogawa: Other Research Support; Modest; AstraZeneca, Astellas, Boehringer lngelheim, Bristol-Myers Squibb, Daiichi Sankyo, Dainippon Sumitomo Pharma, Kowa, MSD, Novartis, Pfizer, Sanofi, Takeda. Other Research Support; Significant; Bayer, Chugai, Otsuka. Honoraria. Honoraria; Modest; AstraZeneca, Bayer, Pfizer, Sanofi, Takeda. Honoraria; Significant; Daiichi Sankyo, MSD.
- © 2014 by American Heart Association, Inc.