Imaging Visualizes Atrial Damage After Procedure

WEDNESDAY, Oct. 1 (HealthDay News) -- A high-resolution MRI method that allows non-invasive visualization and quantification of left atrial scarring after radiofrequency ablation can help predict whether atrial fibrillation will recur after the procedure, researchers report in the Oct. 7 issue of the Journal of the American College of Cardiology.

Christopher J. McGann, M.D., and colleagues from the University of Utah in Salt Lake City, used a three-dimensional delayed-enhancement MRI sequence and novel processing methods to image left atrial scarring before and after radiofrequency ablation in 46 patients undergoing pulmonary vein antrum isolation for atrial fibrillation.

The researchers found that the spatial resolution was 1.25 x 1.25 x 2.5 mm (reconstructed to 0.6 x 0.6 x 1.25 mm) with imaging times ranging from eight to 12 minutes. The left atrial wall was hyperenhanced after ablation, possibly representing tissue scarring, which could be quantified by automated methods. The extent of wall enhancement correlated with arrhythmia recurrence at three months with greater than 13 percent injury was associated with a strong likelihood that atrial fibrillation would not recur (odds ratio 18.5), the report indicates.

"The finding by McGann et al. that the degree of atrial scar after atrial fibrillation ablation correlates directly with freedom from atrial fibrillation lends further support to the hypothesis that generalized rather than targeted atrial debulking by catheter ablation may have an important role in atrial fibrillation suppression," Henry R. Halperin, M.D., and Saman Nazarian, M.D., from Johns Hopkins Hospital in Baltimore, write in an accompanying editorial.

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Editorial