Early lesion visualization after catheter ablation for atrial fibrillation: rationale and preliminary results of the CALAMARI study

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Incomplete atrial lesion is related to high atrial fibrillation (AF) recurrence after Pulmonary vein antrum isolation (PVAI). Objectives The CALAMARI study is a single-center, prospective, observational study with a longitudinal design. The primary aim is to assess PVAI lesion and its development over time using cardiovascular magnetic resonance (CMR). The secondary objective is to identify possible predictors of AF recurrence. Methods 96 consecutive patients undergoing PVAI for paroxysmal AF will undergo four sequential CMR: 1) pre-PVAI CMR 2) post-PVAI CMR, immediately after the ablation 3) CMR one-day or one-week post-PVAI 4) CMR 3-months post-PVAI. Dark-blood short-inversion-time recovery (DB-STIR) will identify oedema. Pre- and post-contrast prepped inversion-recovery with long inversion time (IR-prep) and three-dimensional late gadolinium enhancement (3D-LGE) images will be used to visualize atrial lesion (AL). Qualitative and quantitative assessments of AL will be performed. Patients will be followed-up for 2 years to identify AF recurrence. Preliminary results Ten patients (63.1±5.7 years old, 80% male) completed a pre-PVAI CMR and a post-PVAI-CMR. The AL post-PVAI was visible in 9 patients (90%) using post-contrast IR-prep sequences and in 6 patients (60%) using pre-contrast IR-prep and 3D-LGE. Microvascular obstruction was identified in 7 (70%) patients using IR-prep-post-contrast. On DB-STIR, edema was visualized in all patients with a significant increase in the left atrium wall thickening in CMR post-PVAI vs. pre-PVAI CMR (6.4±2.9 vs. 3.4±1.5, p = 0.09). Conclusion Post-PVAI AL visualization with CMR is feasible in most patients. The CALAMARI study will better understand the AL modifications over time.