DE-CMR offers promise for guiding redo ablations

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 - Electrocardiogram

Delayed-enhancement cardiac MR (DE-CMR) one day may be used to guide reablation procedures to treat atrial fibrillation if results from a feasibility and proof-of-concept study pan out. The study showed DE-CMR accurately identified and localized gaps in patients being reablated because of recurrences.

Radiofrequency ablation for patients with atrial fibrillation has a far from perfect score card. Some patients require repeat ablations after atrial fibrillation recurrences, which may be due to gaps in the pulmonary vein isolation lesions that allow pulmonary vein reconnection.

Animal studies found that DE-CMR could detect gaps in ablation lesions in real time. Felipe Bisbal, MD, of the Hospital Clinic in Barcelona, and colleagues designed their study to evaluate the usefulness of DE-CMR during ablation procedures in humans.

They performed DE-CMR on 15 consecutive patients with recurrences after pulmonary vein isolation who were scheduled for a redo procedure between June 2012 and March 2013. For controls, they used 15 consecutive patients who underwent a second conventional Lasso-technique pulmonary vein isolation. The controls were included to compare procedural duration, radiofrequency and fluoroscopy times.

Bisbal et al identified 67 CMR gaps around pulmonary veins and all of the electrically reconnected pulmonary veins had CMR gaps. Using CMR-guided ablation, they achieved reisolation in 95.6 percent of the reconnected pulmonary veins.

“[A] very high rate of PV [pulmonary vein] reisolation was achieved, targeting only the CMR gaps, which suggests that all conducting gaps could potentially be identified by DE-CMR,” they wrote. “If this hypothesis is confirmed in a larger study, DE-CMR might be proposed as a reliable guide for reablation procedures.”

Compared with controls, DE-CMR had a shorter mean radiofrequency time but not a shorter mean procedural duration or fluoroscopy time. For research purposes, they wanted high-density mapping in the CMR patients, which may have affected overall procedural duration.

Consequently, they proposed the DE-CMR also might reduce ablation time and procedural duration. They suggested that several follow-up studies be conducted to further test a DE-CMR approach for atrial fibrillation reablations.

The study was published in the July issue of the Journal of the American College of Cardiology: Cardiovascular Imaging.