Catheter Ablation -> SVT/AVNRT/WPW/AT: -> Clinical Trials / Outcomes D-PO05 - Poster Session V (ID 39) Poster

D-PO05-157 - Supraventricular Tachycardia Sustained Despite Occurrence Of Sudden Ventriculoatrial Block: A Multicenter Study Of Nodoventricular/nodofascicular-related Orthodromic Reciprocating Tachycardia Vs Atrioventricular Nodal Reentrant Tachycardia (ID 1282)


Background: Supraventricular tachycardias (SVT) sustained despite occurrence of ventriculoatrial (VA) block are rare but need careful interpretation of electrograms to distinguish orthrodromic reciprocating tachycardia (ORT) with nodoventricular/nodofascicular (NV/NF)-fibers from AVNRT with upper common pathway block.
Objective: The aim of this multicenter study (18 centers) was to assess the prevalence and features of these SVTs.
Methods: We analyzed 24 SVTs [10 NV/NF-ORTs (n=7/3) and 14 AVNRTs] sustained with VA block.
Results: The SVT features are shown in the Table. A dual AV-nodal physiology was seen in all patients and a triple AV-nodal physiology was not rare in either SVT. The number of inducible SVTs with different VA intervals was greater in AVNRT than NV/NF-ORT. Wenckebach-type VA block was frequently seen in NV/NF-ORT possibly due to the retrograde conduction block of the slow pathway attached to the NV/NF-fiber. However, the mode of VA block varied in AVNRT. NV/NF-ORT was diagnosed by a His-refractory PVC (n=7), PPI - TCL <115 ms (n=4), and orthodromic His/atrial (n=4/4) capture by RV entrainment pacing. The ROC curves revealed that the best cut-off value of the PPI - TCL excluding AVNRT was 150 ms (AUC: 0.83) with a sensitivity of 67% and specificity of 100%, and the number of inducible SVTs ≥ 2 suggested AVNRT with sensitivity of 71% and specificity of 100% (AUC: 0.82). All procedures were successful, but 2 NV/NF-ORTs and 1 AVNRT recurred.
Conclusion: Wenckebach-type VA block, the number of inducible SVTs ≥ 2, and PPI - TCL <150 ms might be a guide to discriminate NV/NF-ORT from AVNRT.