CardioExchange Archive

CardioExchange’s John Ryan interviews Nassir F. Marrouche, lead author of the DECAAF study, about the use of delayed-enhancement MRI to identify atrial tissue fibrosis in patients who undergo catheter ablation for atrial fibrillation. The study is published in JAMA.

THE STUDY

Researchers prospectively enrolled 329 patients diagnosed with atrial fibrillation who were scheduled to undergo their first catheter ablation procedure at one of 15 centers in the U.S., Europe, and Australia. Delayed-enhancement MRI was performed within 30 days before ablation. Fibrosis was categorized as stage 1 (<10% of the atrial wall), stage 2 (10–<20%), stage 3 (20–<30%), or stage 4 (≥30%). Results in 260 patients with good-quality MRI images and available follow-up data showed significantly elevated risk for recurrent arrhythmia per 1% increase in left atrial fibrosis. Adding fibrosis to a traditional prediction model improved the accuracy of predicting recurrence.

THE INTERVIEW

Ryan: Given your data, if patients have stage 4 atrial fibrosis, they have about a 70% chance of recurrence of atrial fibrillation. Should we even be offering these patients catheter ablation?

Marrouche: Patients with advanced atrial fibrotic disease (stage IV and diffuse stage III) continue to be a challenge for the physician who performs ablations. We and others are studying alternative options for this patient population.

Ryan: How reproducible are the MRIs between centers? Can — and should — this practice be introduced on a larger scale? How many patients are likely not to be candidates for cardiac MRI because they already have devices that preclude the scan?

Marrouche: In DECAAF, the reproducibility of “fibrosis-specific” MRI sequences/acquisition was excellent. Centers went through a 3- to 4-scan learning phase, but acquisition was perfected with training. All MRI scanners can be equipped with the fibrosis-specific sequence. With the introduction of new MRI-compatible pacemakers and defibrillators, scanning these patients’ hearts should no longer be a challenge.

Ryan: Can the location of atrial fibrosis guide the ablation technique?

Marrouche: Indeed, the DECCAF subanalysis presented at the ESC conference in Amsterdam revealed that ablation-induced scarring that covers fibrosis would improve procedural outcomes. We and others are studying this prospectively.

Ryan: Is there a difference in clinical outcomes such as stroke, heart failure, and hospitalization, depending on the stage of atrial fibrosis?

Marrouche: Multiple studies published in the past 5 years correlate atrial fibrosis with stroke risk, left-atrial-appendage clot formation, and heart failure. Atrial fibrosis can be considered in assessing the risks for stroke and heart failure in arrhythmia patients and, possibly, also in high-risk patients who have no history of arrhythmia.

Given the findings of Dr. Marrouche and his colleagues, would you favor the use of delayed enhancement MRI to detect atrial tissue fibrosis in this population?