Magnetic resonance imaging pre and post pulmonary vein isolation for atrial fibrillation: diagnostic accuracy to detect and characterize ablation lesions

Methods Consecutive patients with paroxysmal AF in a randomised study comparing pulmonary vein isolation by wide area circumferential radiofrequency ablation (WACA) to ostial ablation with a cryo-balloon (CRYO) underwent CMR late gadolinium enhancement (LGE) imaging preand 3 months post ablation. Imaging was anonymized for blinded analysis of (1) LGE images, and (2) a 3D fusion image with LGE projected onto a segmented LA surface (thresholding set at 5 SD above mean ventricular signal). Scans were categorised using both assessment techniques separately as pre or post ablation, and if post ablation, whether lesions were in an ostial or WACA distribution. Results LGE imaging was performed in 50 patients (aged 61 ± 10 years, 72% male). Sensitivity and specificity for detection of ablation lesions was 60% and 96% on LGE imaging, or 88% and 82% respectively on 3D fusion imaging. Detection of WACA and CRYO lesion sets were correct in 14/24 and 16/26 respectively on LGE imaging, or 21/24 and 23/26 on 3D fusion imaging. Assessment of lesion distribution was correct for 13/50 from LGE images (4/24 for WACA and 9/26 for CRYO) and 26/50 from 3D fusion images (p = 0.013; 13/24 for WACA and 13/26 for CRYO).