With the aging of the general population, the prevalence of atrial fibrillation (AF) is steadily increasing. Pulmonary vein ablation as treatment for AF is currently favored and in widespread use. The success rate of this procedure in “curing” AF, however, remains marginal and additional diagnostic tools are needed to predict which patients may benefit most from this invasive therapy.
Presented at the European Society of Cardiology Congress in Amsterdam, Netherlands, the Delayed Enhancement-MRI Determinant of Successful Catheter Ablation of Atrial Fibrillation, or DECAAF, study attempted to address this question.
Pre-procedure MRI was obtained in 260 patients with AF, including 65% with paroxysmal AF, to identify the degree of atrial remodeling and fibrosis, which can create a nidus for the arrhythmia. The amount of fibrosis was used to classify the patients into 4 groups (stage 1 through 4); adjustment was made for demographic variables, comorbidities, type of AF, volume of the left atrium, and left ventricular ejection fraction.
In the multivariate model, the extent of atrial fibrosis emerged as the only significant predictor of recurrence of AF post-procedure (each 1% increase in atrial fibrosis increased the post-ablation risk of recurrence by 5.8%). For patients with <10% fibrosis, approximately 85% were free from AF at 1 year follow-up compared with only 31% who were AF-free if atrial fibrosis was ≥30%.
Not only does this study have implications for predicting the success of this procedure, it also suggests that the location of the ablation therapy, which has traditionally targeted the pulmonary veins, can instead now be guided by MRI-identified fibrosis.
For patients with AF who cannot be successfully managed with medical therapy, ablation is often indicated. A discussion with patients who are potential candidates may soon include information about pre-procedure cardiac MRI and its role in predicting the success of the ablation and in localizing fibrosis in order to better direct therapy.