Delayed-enhancement MRI (DE-MRI) before ablation treatment can stage the degree of damaged heart tissue and help predict whether treatment will be effective, researchers found.
The results are from the Delayed-Enhancement MRI Determinant of Successful Radiofrequency Catheter Ablation of Atrial Fibrillation (DECAAF) trial, led by Dr. Nasir Marrouche from the Comprehensive Arrhythmia Research and Management (CARMA) Center at the University of Utah.
The DECAAF trial included 260 atrial fibrillation patients (mean age, 59 years) from 15 medical centers in the U.S., Europe, and Australia.
DE-MRI was performed up to 30 days before ablation in all patients to determine the presence and extent of atrial fibrosis. Postablation DE-MRI was performed 90 days later as a follow-up in 177 of the patients to determine the extent of residual ablation.
At the 90-day follow-up, recurrence of arrhythmia was noted in 88 (34%) of the 260 patients based on Holter monitors and electrocardiograms.
Using multivariate analysis, the researchers identified two independent predictors of successful ablation or recurrent symptoms: stage of atrial fibrosis before ablation and residual fibrosis after ablation.
Patients whose preablation fibrosis was stage I (< 10% damaged atrial tissue) had an 86% success rate, while those with stage II fibrosis (10%-20% damage) had a 63% success rate. Patients with stage III fibrosis (20%-30% damage) had a 55% success rate and those with stage IV (> 30% damage) had a 31% success rate.
For every increased percentage of fibrosis before ablation, there was a 6.3% increased risk of recurrent symptoms after ablation. In addition, for every percentage of residual fibrosis, there was an 8.2% increased risk of recurrent symptoms.
By performing DE-MRI before ablative treatment, physicians can triage patients according to the likelihood of treatment success and avoid ablative procedures in patients for whom they are unlikely to work, Marrouche and colleagues noted.
