ATP Challenge After Pulmonary Vein Isolation

Sep 03, 2015
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Authors:
Kobori A, Shizuta S, Inoue K, et al.
Citation:
Adenosine Triphophate-Guided Pulmonary Vein Isolation for Atrial Fibrillation: The Unmasking Dormant Electrical Reconduction by Adenosine Triphosphate (UNDER-ATP) Trial. Eur Heart J 2015;Aug 30:[Epub ahead of print].
Summary By:
Fred Morady, MD, FACC

Study Questions:

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)?

Methods:

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.

Results:

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%).

Conclusions:

Additional ablation for ATP-induced PV reconnection after PVI does not improve the clinical outcome of RFCA in patients with AF.

Perspective:

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.

Keywords: Adenosine, Adenosine Triphosphate, Arrhythmias, Cardiac, Atrial Fibrillation, Atrial Flutter, Catheter Ablation, Electrophysiologic Techniques, Cardiac, Pulmonary Veins, Risk


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