P-173 Unexpected High Prevalence of Left Nodal Extension Breakthrough in Patients with Slow fast Atrioventricular Nodal Reentry Tachycardia

Chih-Chieh Yu, Bui The Dung, Liang-Yu Lin, Fu-Chun Chiu, Chia-Ti Tsai, Ling-Ping Lai, Jiunn-Lee Lin

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Background: Dual pathways inside atrioventricular node (AVN) have been postulated as the critical component of the circuit of AVN re-entry tachycardia (AVNRT). However, detailed electroanatomical mapping is lacking so far.
Methods: To investigate the 3-dimensional circuit incorporating both right and left AVN extensions, we studied 17 pts of slow-fast AVNRT by a duodecapolar electrode positioned along the tendon of Todaro, a decapolar electrode placed
along the high septum of left ventricle, and a decapolar one in the coronary sinus. The fast pathway of AVN was recorded as the earliest retrograde atrial activation site (RAA) during right ventricular pacing (RVP) and slow-fast
AVNRT. Ventricular extrastimuli were recruited during AVNRT to demonstrate the atrial activation sequence. Results: The RAAs in AVNRT were at right septum in 6 pts (35.3%), left in 4 (23.5%), simultaneous in 7 (41.2%). In the 13 patients whose RAAs involved right septum, the RAA was mainly at anteroseptal area in 10 pts (77%), less at middle and posterior septum (2 pts, 15%), and one patient
showed broad breakthrough. During RVP at comparable cycle length, RAA was at right septum in 7 pts (41.2%), left in 3 (17.6%), simultaneous in 7 (41.2%). The RAAs were concordant between AVNRT and RVP in most of the pts
(15 pts, 88.2%). Conclusion: This electroanatomical mapping study showed
unexpected high prevalence of left nodal extensionn breakthrough and the pattern of retrograde fast pathway atrial breakthrough could be variable in each patient.
Original languageChinese (Traditional)
Pages (from-to)S101
JournalGlobal Heart
Publication statusPublished - May 1 2009
Externally publishedYes

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