In a cohort study that used late gadolinium enhancement magnetic resonance imaging (LGE-MRI) to evaluate left atrial (LA) scarring, investigators showed that balloon cryoablation resulted in more scarring compared with point-by-point and multipolar radiofrequency (RF) ablation. These data from a cohort of the DECAAF study [Marrouche NF et al. JAMA. 2014] were presented in a poster by Nazem W. Akoum, MD, University of Washington, Seattle, Washington, USA.

The DECAAF study showed an independent association between atrial tissue fibrosis estimated by delayed enhancement MRI and the likelihood of recurrent arrhythmia among patients with AF undergoing catheter ablation [Marrouche NF et al. JAMA. 2014]. Pulmonary vein isolation (PVI) is commonly used for catheter ablation of atrial fibrillation (AF). The current cohort study used LGE-MRI to evaluate LA scarring resulting from the techniques used for PVI in the DECAAF study.

The study comprised 111 patients with paroxysmal and persistent AF who underwent PVI without additional ablation. Overall scar and pulmonary vein encirclement were compared across 3 different techniques. Point-by-point irrigated RF ablation was used in 91 patients (82.0%), duty-cycled multipolar RF ablation catheter in 8 patients (7.2%), and balloon cryoablation in 12 patients (10.8%). LGE-MRI was obtained 3 months following ablation.

The baseline characteristics of the study participants were not significantly different. The mean age of the mostly male cohort was about 68 years. The most frequent major comorbidities were hypertension, diabetes, and heart failure. Persistent AF was present in 35% of patients, mean left ventricular ejection fraction was 59%, and the mean LA volume was 99 mL. Approximately 20% of patients had evidence of atrial fibrosis.

Overall scarring was highest in the cryoablation group (13.4 ± 6.2%), followed by the point-by-point irrigated RF (10.5 ± 4.3%) and the duty-cycled multipolar RF groups (7.1 ± 2.3%; P < .01 for the group comparison).

Scarring completely encircling all 4 pulmonary veins occurred in 1 of 12 patients (8.3%) in the cryoablation group, 7 of 91 patients (7.7%) who received point-by-point ablation, and no patients in the multipolar RF group.

Balloon cryoablation resulted in more LA scarring compared with the other techniques. All techniques were poor in achieving complete pulmonary vein encirclement. In this cohort, neither overall scarring nor complete pulmonary vein encirclement was a significant predictor of arrhythmia recurrence.

This study suggests that the type of ablation used has an impact on scarring but not necessarily on procedural success. Further, ablation of the pulmonary veins did not predict recurrent arrhythmias, supporting the findings from the DECAAF study, which suggested that rather than targeting the pulmonary veins, procedures that ablate fibrotic tissue might produce better outcomes.