P1417Ablation lesions from laser and radio-frequency pulmonary vein isolation compared by magnetic resonance imaging

Abstract

Background: Ablation lesions differ by technology used. Their characteristics can be assessed with Delayed-Enhancement Cardiac Magnetic Resonance (DE-CMR). Objective(s): To compare laser ablation lesions to radiofrequency (RF) lesions in pulmonary vein isolation (PVI). Method(s): A cohort of patients with laser-ablated paroxysmal AF was compared to RF patients matched by age, gender and AF type. DE-CMR sequences were acquired 3 months post-PVI. Extent and location of fibrosis was assessed with ADAS-AF software (Galgo Medical). DE-CMR ablation gaps were defned as vein sections showing no enhancement. Gap percentage for each vein was computed as total mm of gap divided by total vein perimeter and fibrosis percentage as fibrosis area divided by total atrial area (including ~1 cm of vein segment, excluding mitral area). Normalized fibrosis area was defned as fibrosis percentage divided by total non-gap percentage. Result(s): From the cohort of 15 laser patients, one was excluded from analysis for lack of DE-CMR and two because PVI was not complete due to complications in the procedure. Gap percentage, fibrosis area and normalized fibrosis area were computed for 12 laser patients and matched RF cases. Laser patients had significantly smaller gap percentage than RF patients: 9.5%+/-10.3% of gap for left veins and 30.5%+/-25.2% of gap for right veins, compared to 34.4%+/-24.4% and 50.5%+/-30.3%, respectively. Fibrosis area was comparable for both groups (laser: 22.6%+/-10.9%, RF: 21.4%+/-12.8%), but significantly smaller in laser patients when normalized by non-gap percentage (17%+/-7.2% vs. 38.1%+/-9.3% in RF patients). Full DE-CMR isolation was achieved at 25% of laser-ablated veins and 8.3% of RF-ablated veins. Mean laser procedure time was 189.5 minutes, with 25.1 minutes of fuoroscopy time, compared to 135.6 minutes for RF procedures, with 23.6 minutes of fuoroscopy. Recurrences at 6 months presented no statistically significant difference: 25% (3 out of 12) of laser patients recurred, compared to 17% (2 out of 12) of RF patients. Conclusion(s): Laser ablation requires longer procedure time but DE-CMR images show less gap and smaller fibrosis area compared to RF ablation. Procedure duration for laser may be longer due to operators being still in the learning curve.