Abstract 4108: Myocardial Injury Can Be Identified by Magnetic Resonance Imaging in the Course of Ablation Procedures for Atrial Fibrillation
Background: Pulmonary vein antrum isolation (PVAI) is regarded as an effective therapy in patients with atrial fibrillation (AF). Extension and location of ablation lesions often remain unclear during the procedure. We report a new approach on visualization of myocardial injury using magnet resonance imaging (MRI) during PVAI procedure.
Methods: Patients who underwent PVAI, received MRI before and at the terminal phase of PVAI. Delayed enhancement (DE-) MRI sequences were applied, and maximum intensity projections (MIP) obtained. Myocardial injury size was then measured on manually segmented 3D images by a computer algorithm using dynamic thresholding.
Results: 30 patients received PVAI from January 2008 to May 2008. In a subset of 15 patients, MRI was performed before and during the procedure. Using DE-MRI, the average lesion to healthy myocardium ratio was 7.56±1.27% during PVAI. The figure⇓ shows an example of MIP of a DE-MRI scan in 2D (A,B) and 3D segmentation (C,D) in a anterior view pre (A,C), and during PVAI (B,D). Myocardial injury is identifiable as white tissue around PV single ostia (full arrows) and common trunk (dashed arrows).
Conclusions: Using MRI is feasible in the course of ablation procedures. In PVAI patients, DE-MRI allowed identification of location and extension of myocardial injury. Therefore, this new MRI approach might improve ablation techniques, and thus long-term success of PVAI.