DENVER — Using delayed enhancement MRI, researchers for the DECAAF study demonstrated that atrial fibrosis is a strong, independent predictor of outcome in patients undergoing ablation for atrial fibrillation.
The prospective, double blind study included 330 patients (mean age, 59 years; 69% men; 64% paroxysmal AF) at 15 centers in Australia, Europe and the United States with varying degrees of expertise in cardiac MRI. All patients underwent high-resolution delayed enhancement MRI up to 30 days before ablation. AF ablation was performed and patients were followed up at 3, 6 and 12 months for recurrence using Holter monitors and ECGs.
Atrial fibrosis was successfully quantified in 273 patients (stage 1, <10% fibrosis; stage 2, 10% to 20%; stage 3, 20% to 30%; stage 4, >30%).
Patients were followed for 1 year after ablation. The final cohort included 261 patients with good delayed enhancement MRI scans who completed at least 90 days of follow-up. Seventeen percent of images could not be analyzed due to poor-quality MRI.
Nassir F. Marrouche
According to results, recurrent arrhythmia was observed in 94 of 261 patients. A multivariate Cox proportional hazards model was used to evaluate arrhythmia recurrence. Atrial fibrosis was strongly associated with arrhythmia recurrence independent of age, sex, participating site, atrial volume, AF type and medical comorbidities (HR=1.0562). On average, every 1% increase in fibrosis is associated with a 6.2% increase in the hazard of recurrence when other clinical factors are held constant, Nassir F. Marrouche, MD, director of the cardiac electrophysiology laboratories at University of Utah, said at a press conference. Patients with stage 1 fibrosis had an AF ablation success rate of 85%; stage 2, 67%; stage 3, 55%; and stage 4, 30%.
In this study, the only predictor of fibrosis was the presence of hypertension, Marrouche said.
“Delayed enhancement MRI-based quantification of atrial fibrosis is a strong predictor for AF ablation outcome. Moreover, delayed enhancement MRI detected atrial fibrosis in AF patients and was shown to be feasible and reproducible in multiple MRI-experienced as well as non-experienced centers across the world,” Marrouche said. – by Deb Dellapena
For more information:
Marrouche N. LB01-04. Presented at: Heart Rhythm Society’s Annual Scientific Sessions; May 8-11, 2013; Denver.
Disclosure: Marrouche reports receiving consulting fees from Boston Scientific Corp., eCardio, Estech and Sanofi-Aventis; equity interests in Surgivision; and research grants from eCardio and Estech.