Ra Fx ablation of Atrioventricular nodal reciprocating tachycardia

Dr. R. Sakthivel

Consultant, Cardiologist, Kauvery Hospital, Heart City, Trichy

Dr R Sakthivel

A 55 years Female presents with recurrent episodes of palpitation and is documented to have narrow QRS tachycardia responsive to adenosine.

Tachycardia ECG was suggestive of atrioventricular nodal reciprocating tachycardia (AVNRT).

An electrophysiology study (EPS) was done and supraventricular narrow complex tachycardia was inducible with 1:1 ventriculo-atrial (VA) relationship and short VA of 15 ms. Tachycardia spontaneously terminated with A and a VAV response was seen with RV overdrive with cPPI-TCL and SA-VA were indicative of AVNRT.

Ablation was done at the slow pathway region (right inferior extension) guided by fluoroscopy and electrograms with 40 Watts power and 55í‚°C temperature initially below and at the coronary sinus (CS) ostium and then inside the proximal CS, but the ablation was unsuccessful with easy inducibility despite multiple attempts and usage of the sheath for stability.

Attempted to ablate the left inferior extension as a last resort and the slow pathway region near the left posteromedial mitral annulus was accessed via transseptal access guided by electrograms (smallish A and large V with high-frequency SP potential at the end of A). Junctional with retrograde VA conduction was seen during ablation. Tachycardia was notably non-inducible for the first time after this ablation attempt that persisted for 15 min wait time.

Left septal ablation targeting the left inferior nodal extension is an alternative strategy when AVNRT is refractory to right (posterior) septal ablation (Figs. 1 and 2).


Fig. 1. Ablation of left-sided slow pathway extension near the posteromedial mitral annulus.


Fig. 2. Electrograms at the left-sided slow pathway region. Junctional with VA conduction noted during ablation. References

1.Katritsis DG, et al. Left septal slow pathway ablation for atrioventricular nodal reentrant tachycardia. Circ Arrhythm Electrophysiol. 2018;11(3):e005907.

2.Kumar Narayanan, et al. Left sided ablation for atrioventricular nodal re-entrant tachycardia: frequency, characteristics and outcomes. Indian Pacing Electrophysiol J. 2021;21(1):5-10.