Should fast pathway ablation be reconsidered in typical atrioventricular nodal re‐entrant tachycardia?

Abstract

Introduction Atrioventricular nodal re‐entry tachycardia (AVNRT) is the most common, regular narrow‐complex tachycardia. The established treatment is catheter ablation of the AV nodal slow pathway (SP). However, in a select group of patients with long PR intervals in sinus rhythm, SP ablation can lead to AV block due to the absence of robust anterograde conduction through the fast pathway (FP). This report aims to demonstrate that AV nodal FP ablation is a reasonable approach in patients with AVNRT and poor or absent anterograde FP conduction. Methods and Results Standard electrophysiology study techniques were used in the electrophysiology laboratory. Catheter ablations were performed using radiofrequency energy. Mapping of intracardiac activation was performed with electroanatomical mapping systems. Outcomes were assessed acutely during the procedure and during routine clinical follow‐up. Six patients with first‐degree AV block and recurrent AVNRT who underwent ablation of their tachycardia at our institution are presented. One patient underwent ablation of AV nodal SP resulting in high‐degree AV block necessitating pacemaker implantation. The remaining five patients underwent ablation of the AV nodal FP guided by electroanatomical mapping of the earliest atrial activation in tachycardia. These five had successful treatment of the tachycardia with preservation of anterograde AV nodal conduction. Mapping and ablation approach to eliminate retrograde FP conduction are described. Conclusion In select patients with AVNRT and poor anterograde FP conduction, retrograde FP ablation is reasonable and is less likely to result in AV block and pacemaker dependency.

Fast pathway ablation in a patient with PR prolongation

“…Five cases of FP were successful with no need for any pacemaker implantation. Average PR interval was 294 ms (range 230-415 ms) 10. Discordance is noticed in the fast pathway of the described patient.Despite having an absent anterograde conduction, the retrograde conduction in this pathway was robust and by itself rendered the patient's tachycardia incessant.…”

“…Five cases of FP were successful with no need for any pacemaker implantation. Average PR interval was 294 ms (range 230‐415 ms) 10 …”

“…Anterograde conduction in some cases is poor or sometimes absent through the fast pathway. 10 We report a patient with typical AVNRT with an absent anterograde conduction of the fast pathway treated with ablation of the retrograde fast pathway.…”

Retrograde fast pathway cryoablation inside the coronary sinus for slow‐fast atrioventricular nodal reentrant tachycardia in a patient with persistent left superior vena cava

“…In patients with prolonged PR intervals and no antegrade dual AV nodal physiology, especially those with a PR interval exceeding 300 ms, slow pathway ablation carries a risk of AV block. Retrograde fast pathway ablation has been reported as an effective method for reducing the risk of AV block in patients with markedly prolonged PR intervals 14 . For such patients, retrograde fast pathway ablation may be more appropriate than antegrade slow pathway ablation.…”

“…Retrograde fast pathway ablation has been reported as an effective method for reducing the risk of AV block in patients with markedly prolonged PR intervals. 14 For such patients, retrograde fast pathway ablation may be more appropriate than antegrade slow pathway ablation. However, retrograde fast pathway ablation by radiofrequency energy for patients with PLSVC still poses a substantial risk of AV block due to unexpected antegrade slow pathway injury because of the deformation of the triangle of Koch.…”