DENVER — Cardiac fibrosis measured on MRI appears to predict the success of ablation for atrial fibrillation, a study showed.

Each 1% greater fibrosis was associated with a 6% higher risk of recurrence of the arrhythmia after ablation in a multivariate model (P<0.0001), Nassir Marrouche, MD, of the University of Utah in Salt Lake City, and colleagues found.

Only 31% of individuals with the highest degree of fibrosis remained free of atrial fibrillation at around a year and a half after their procedure to terminate it compared with 86% in those with the least fibrosis.

Hypertension was the only predictor of fibrosis, not atrial fibrillation or other characteristics, the group reported at a late-breaking session here at the Heart Rhythm Society meeting.

“Hopefully this will help us better individualize treatment,” Marrouche said at a press conference, noting that currently at least 30% of ablations fail to produce a persistent sinus rhythm.

“This is a start to better refine a patient population who are eligible for atrial fibrillation ablation,” he said, suggesting that physicians should be careful approaching the later stages of fibrosis that they aren’t likely to have an impact on with a procedure that does carry some risks.

MRI or 3-D CT is standard to assess anatomy before ablation, so it would be a relatively simple step to add a sequence to analyze fibrosis, Marrouche pointed out.

“We’re recommending, yes, every single Afib patient, before you touch their heart you should know how much disease they have, how extensive their disease is,” he told reporters.

At the very least, this data should help in counseling patients, John D. Day, MD, of the Intermountain Medical Center in Salt Lake City, told MedPage Today.

“If you have a patient who has extensive disease, this could be very helpful when you meet with the patient because you could say ‘This is really a long shot that we can maintain normal rhythm,’ or conversely we may tell a patient ‘Your atrium looks very healthy. I would expect an excellent procedural success.”

The results also highlight the need to intervene early in the disease process before there is extensive fibrosis, said Day, who acted as session and press briefing moderator but was not involved in the study.

The prospective DECAAF (Delayed Enhancement MRI Determinant of Successful Catheter Ablation for Atrial Fibrillation) study included 261 patients getting a first ablation procedure for atrial fibrillation at 15 centers who had a usable MRI scan and at least a year of follow-up.

Patients got a delayed enhancement MRI up to 30 days before their procedure, which was sent to a core lab blinded by not showing the fibrosis results to the physician or the ablation outcomes to the core lab analyst.

Out of 30 characteristics analyzed, including the CHADS2 risk score, left ventricular ejection fraction, age, heart disease, and mitral valve disease, only hypertension predicted fibrosis (P=0.004).

Source: MedPage Today.