Atypical Atrioventricular Nodal Reentry Tachycardia with Eccentric Retrograde Left-Sided Activation of Coronary Sinus

Abstract

Background: Recent anatomical and electro- physiological studies demonstrated, that in the human atrioventricular node there are two main extension, rightward and leftward posterior nodal extension (LPNE). The occurrence of eccentric retrograde atrial activation has been demonstrated to be from 6 to 8% in patients with AVNRT by several previous reports. Objectives: The study was performed to confirm that standard right atrium ablation is effective and successful for atrioventricular node reentry tachycardia (AVNRT) with eccentric retrograde left-sided activation, masquerading a tachycardia which look like as a tachycardia using left accessory pathway. Methods and Results: During a 7 years period (from 2002 to 2008), 865 consecutive patients underwent electrophysiological study. In the group with atrioventricular node reentry tachycardia (AVNRT) there were 178 patients. In the group with typical fast-slow AVNRT (162 pts) there was concentric retrograde activation of the both atrium. The 16 patients were with atypical AVNRT (10 pts with slow-slow AVNRT and 6 pts with LPNE). The ablation was performed, in all patients in the triangle of Koch on the slow pathway of atrioventricular node. The successful rate of ablation was 99.4 % (177/178 pts). The incidence of AVNRT with eccentric retrograde activation was 3.4%. In the follow up period (16 + 12 months), there is no recurrence of AVNRT in the group with LPNE. Conclusions: This study demonstrated the different electrophysiologic characteristics between the AVNRT patients with eccentric and concentric retrograde atrial activation. Standard ablation, but a little bit higher in the triangle of Koch, closer to the fast pathway, in the right atrium is effective and successful for AVNRT with retrograde left eccentric conduction in the coronary sinus.