Ablation of atrial fibrillation: does the addition of three-dimensional magnetic resonance imaging of the left atrium to electroanatomic mapping improve the clinical outcome?

To compare in a randomized and prospective fashion the outcome of atrial fibrillation (AF) ablation either after one procedure or after two procedures using the Carto-XP vs. the Carto-Merge mapping system in two different AF populations. Two hundred and ninety-nine patients with paroxysmal and persistent AF were enrolled in the study. One hundred and fifty patients with paroxysmal or persistent AF were randomly assigned to the Carto-Merge group and 149 patients to the Carto-XP group. The Carto-Merge patients underwent magnetic resonance imaging (MRI) of left atrium (LA) the day before the ablation. The ablation scheme included electrical disconnection of the pulmonary veins plus linear lesions. In the Carto-Merge patients, the three-dimensional MRI of the LA reconstruction merged with the electroanatomical map, and in the Carto-XP patients, the electroanatomical map guided the procedure. Considering the overall population with paroxysmal AF, 54% maintained sinus rhythm (SR), whereas in the persistent AF population, SR was present in 43% of the patients at the 12-month follow-up. In patients with paroxysmal AF, 52% in the Carto-XP group and 55% in the Carto-Merge group maintained SR without drugs. Procedure durations and exposure to X-ray in the Carto-XP group were 94.6 +/- 17.5 and 40.4 +/- 13.5 min, respectively. In the Carto-Merge group, duration and X-ray exposure were 89 +/- 41.6 and 22.1 +/- 11.4 min, respectively. Considering the patients with persistent AF at the12-month follow-up, 44% in the Carto-XP group and 42% in the Carto-Merge group maintained SR without drugs. Procedure durations and X-ray exposure in the Carto-XP group were 102.9 +/- 22.9 and 58 +/- 8.7 min, respectively. In the Carto-Merge group, both duration and X-ray exposure were 114.4 +/- 50.9 and 28.8 +/- 14.3 min, respectively. Image integration using Carto-Merge in patients undergoing catheter ablation for paroxysmal and persistent AF does not significantly improve the clinical outcome, but shortens the X-ray exposure.