Abstract 14928: Significance of Slow Potential Recorded at the Slow Conduction Zone in Verapamil-sensitive Atrial Reentrant Tachycardia Originating From the Atrioventricular Annulus
Background: Calcium-channel dependent tissue (Ca-DT) forms the slow conduction zone (SCZ) of the reentry circuit in verapamil-sensitive atrial tachycardia originating from the atrioventricular annulus (AVA-AT). This suggest the presence of specific electrogram which reflects the Ca-DT at the SCZ in AVA-AT, as slow potential is recorded at the slow pathway area in AV nodal reentrant tachycardia.
Objective: The purpose of this study was to elucidate whether there is a specific electrogram which represents the Ca-DT of the SCZ in AVA-AT.
Methods: In 21 AVA-AT, the proximity of SCZ was identified by the rapid atrial pacing from which manifest entrainment and orthodromic capture of the earliest atrial activation site (EAAS) were observed. To define the entrance site of SCZ, radiofrequency energy was delivered starting at a site 2 cm proximal to the EAAS and then gradually advanced toward EAAS until termination of AVA-AT. The electrogram morphology at successful site (i.e., entrance site of SCZ) was compared with that at unsuccessful site during sinus rhythm to explore whether there is a specific electrogram which represents the Ca-DT of SCZ.
Results: Manifest entrainment was observed in all patients. AT was terminated by the energy delivery applied proximal to the EAAS in the direction of manifest entrainment pacing site in all patients. A discrete and low amplitude deflection with a slow rate of rise occupying the interval between the atrial and veutricular potentials (i.e., slow potential) was observed during sinus rhythm at all 21 successful sites, but was observed in only 7 unsuccessful sites (p<0.0001). There was no significant difference in the atrial electrogram amplitude and width between the successful and unsuccessful sites (0.38±0.27 vs. 0.47±0.44 mV, and 38.7±10.5 vs. 39.3±9.7 msec, p=NS). However, the electrogram amplitude and width of slow potential at successful site were significantly greater than those at unsuccessful site (0.10±0.04 vs. 0.04±0.05 mV; p=0.001, and 41.2±15.0 vs. 13.5±14.6 msec; p<0.0001).
Conclusions: Slow potential is observed during sinus rhythm at the entrance site of the SCZ of the reentry circuit in AVA-AT, suggesting that this low amplitude with a slow rate of rise potential reflects the characteristics of the Ca-DT.
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: Other Research Support; Modest; Medtronic Japan, Nihon Kohden, Boston scientific, St Jude Medical, Japan Lifeline, Fukuda Denshi, Neotec Japan, Shionogi.. M. Ito: None. S. Kaneko: None. Y. Kanemaru: None. T. Kiyama: None. H. Ogawa: Other Research Support; Modest; Eisai Co.,Ltd.. Other Research Support; Significant; Abbott Vascular Jaoan, Bayer Yakuhin, Ltd., Boehringer Ingelheim Japan, Boston Scientific Japan K.K., Chugai Pharmaceutical Co.,Ltd., Daiichi Sankyo Co., Ltd., Dainippon Sumitomo Pharma Co., Ltd., Fuk. Honoraria; Modest; AstraZeneca K.K, Eisai Co.,Ltd, Otsuka Pharmaceutical Co, Ltd, Takeda Pharmaceutical Co., Ltd, Teijin Pharma Co., Ltd.. Honoraria; Significant; Bayer Yakuhin, Ltd., Daiichi Sankyo Co., Ltd., MSD K.K..
- © 2016 by American Heart Association, Inc.