Predictors of Long-Term Success After Catheter Ablation of Atriofascicular Accessory Pathways
What are the long-term outcomes after radiofrequency catheter ablation (RFCA) of atriofascicular bypass tracts (AFBTs)?
Thirty-four patients (mean age 37 years) underwent RFCA of an AFBT causing antidromic tachycardia. A total of 34 RFCA procedures were performed in these 34 patients between 1992 and 2010. Interviews and electrocardiograms were performed a mean of 9.3 years after the last RFCA procedure.
The AFBT was successfully ablated in 68% of patients. In three patients (9%), there was mechanical block of the AFBT and RFCA was performed at the site of mechanical block. In five patients (15%), conduction through the AFBT was slowed, but not blocked. Atrioventricular node fast pathway ablation was performed in two patients. During a mean of 112 months of follow-up, 24 patients (71%) had no recurrence of paroxysmal tachycardia. Another seven patients (20%) reported a reduction in frequency of episodes. A total of 10 patients (30%) were taking an antiarrhythmic drug. The long-term success rate was 87% in patients in whom the AFBT was completely blocked by ablation during the RFCA procedure. The only predictor of long-term efficacy was ablation-induced complete block of the AFBT.
The authors concluded that there is a low probability of recurrent tachycardia when AFBT conduction is completely eliminated by RFCA.
Of note is that 6/8 patients (75%) with mechanical block or slowing of ABT conduction had recurrent tachycardia during follow-up. This confirms that the only reliable ablation endpoint in patients with an AFB (or other type of accessory pathway) is complete pathway block induced by ablation.
Keywords: Tachycardia, Paroxysmal, Follow-Up Studies, Catheter Ablation
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