CMR and Arrhythmic Substrate Characterization

CMR and Arrhythmic Substrate and Ablation Lesion Characterization

In our research, we conduct pre- and post-ablation imaging in atrial fibrillation patients undergoing pulmonary vein isolation. Our focus lies in examining variations in post-ablation lesion characteristics, volumes, and function among patients undergoing different ablation strategies. Using pre-ablation 3D LGE imaging of the left ventricle, we assess arrhythmogenic substrates for ventricular tachycardia ablations, aiming for precise treatment strategies and improved patient outcomes.

The EVALUATE-PVI and Q-POWER Study

The EVALUATE-PVI and Q-POWER Study focuses on the evaluation and characterization of left atrial (LA) ablation lesions after pulmonary vein isolation (PVI) in atrial fibrillation (AF) patients. In both studies, AF patients undergo a CMR scan before ablation, and <72 hours and 3 months after ablation. Our focus lies in examining variations in post-ablation lesion characteristics, volumes, and function among patients undergoing different ablation techniques. Additionally, we assess collateral tissue damage, including potential esophageal injury and the development of acquired atrial stiffness after ablation. During these studies, we also investigate the clinical outcomes following PVI and explore the utility of LA LGE imaging three months post-PVI. We aim to determine whether such imaging can detect gaps in ablation lines and serve as a predictive marker for AF recurrence.

Electroanatomical mapping

In addition to pre- and post-ablation CMR assessments of the left atrium (LA), we utilize invasive electroanatomical mapping before and after pulmonary vein isolation (PVI). These mapping systems can identify regions of abnormally conductive or 'low voltage' tissue in the LA, aiding in the detection of fibrosis presence, location, and extent. Pre-procedural LGE CMR imaging offers valuable insights before ablation by assessing LA fibrosis. The combination of low voltage areas on electroanatomical maps with regions of high signal intensity on 3D LA LGE may assist in improving ablation outcomes. Our research focuses on validating the relationship between left atrial low voltage areas on electroanatomical maps and the presence of left atrial LGE on CMR before PVI. This approach deepens our understanding of the anatomical and electrical substrates of atrial fibrillation, potentially advancing treatment strategies.

Ablation lesion visualization

During our research, we aim to explore the most accurate CMR techniques for the assessment of ablation lesions in the (sub) acute stage and chronic stage after PVI. Non-contrast-agent-enhanced T1-weighted imaging using long inversion time (TWILITE) has been proposed for the acute assessment of atrial and ventricular ablation lesions. The state-of-the-art review of Hopman and van Pouderoijen, et al. provides an overview of the contemporary CMR strategies to visualize atrial ablation lesions in both the acute and chronic post-ablation stages, focusing on their strengths and limitations. It appears that the TWILITE sequence may be superior to other CMR techniques for the peri- and acutely post-procedural assessment of acute ablation lesions. In our research, we assess the different CMR techniques for ablation lesion visualization during interventional CMR procedures, <72 hours after PVI and 3 months after PVI.