ATP Challenge After Pulmonary Vein Isolation
Does the elimination of adenosine triphosphate (ATP)-induced pulmonary vein (PV) reconnection by additional ablation improve clinical outcomes after radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF)?
The 2,113 patients (mean age 63 years) in the UNDER-ATP multicenter study underwent pulmonary vein isolation (PVI) for AF (paroxysmal in 67%). They were randomly assigned to ATP-guided PVI (n = 1,112) or conventional PVI (n = 1,001). In the ATP group, each PV was challenged with 0.4 mg/kg of ATP a median of 57 minutes after initial PVI and additional RFCA was performed if there was reconnection.
ATP challenge resulted in PV reconnection in 27.6% of patients in the ATP-guided group. The dormant conduction was successfully eliminated by additional RFCA in 98.4% of these patients. At 1 year of follow-up, there was no significant difference in freedom from AF/flutter off drugs between the ATP-guided group (68.7%) and the conventional PVI group (67.1%).
Additional ablation for ATP-induced PV reconnection after PVI does not improve the clinical outcome of RFCA in patients with AF.
This highly-powered and well-designed study provides strong evidence that adenosine-guided PVI does not reduce the probability of recurrent AF after PVI. In contrast, the ADVICE study (Lancet 2015;386:672-9) concluded that adenosine-guided PVI reduces the relative risk of recurrent AF by 56%. However, the latter study was much smaller, had a waiting period between initial PVI and adenosine injection that was approximately half as long as in the present study, and had a much higher reconnection rate (53% vs. 27.6%). The clinical value of adenosine challenge diminishes as the technique used for PVI improves and the waiting time before adenosine administration increases.
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