Left sided ablation for Atrioventricular Nodal Re-entrant Tachycardia: Frequency, Characteristics and Outcomes

BACKGROUND: Left-sided ablation, targeting left inferior AV nodal extensions, is thought to be necessary for success in a small proportion of atrioventricular nodal re-entrant tachycardia (AVNRT) ablations; however Indian data are scarce in this regard. METHODS: Consecutive cases of AVNRT undergoing slow pathway ablation in a single centre over an 18-month period were retrospectively analyzed. Left-sided ablation at the posteroseptal mitral annulus was performed if right-sided ablation failed to abolish AVNRT. RESULTS: From January 2017 to June 2018, out of 215 consecutive supraventricular tachycardia (SVT) cases, 154 (71.6%) were AVNRT (47.1 ± 13.1 years, 46.1% male). Trans-septal ablation was required in 5 (3.2%) cases (mean age 48.8 ± 9.4 years; 4 female, 1 male); all with typical (slow-fast) form of AVNRT. Compared with cases needing only right-sided ablation, radiofrequency time (50.8 ± 16.9 vs. 9.9 ± 8.5 min; p = 0.005) and procedure time (166.0 ± 35.0 vs 79.6 ± 35.9 min; p = 0.004) were significantly longer for trans-septal cases, while baseline intervals and tachycardia cycle length were not significantly different. Junctional ectopy was seen in only 2 of the 5 cases during left-sided ablation, but acute success (non-inducibility) was obtained in 3 cases. There were no instances of AV block. Over mean follow-up of 12.2 ± 4.0 months, clinical recurrence of AVNRT occurred in one case, while others remained arrhythmia-free without medication. CONCLUSION: Left-sided ablation was required in a small proportion of AVNRT ablations. Trans-septal approach targeting the posteroseptal mitral annulus was safe and yielded good mid-term clinical success.