PO-03-090 NOVEL HIGH RESOLUTION MR IMAGING IMPROVES PRE-PROCEDURE IDENTIFICATION OF ABLATION TARGETS IN POST-INFARCT VENTRICULAR TACHYCARDIA

Abstract

MRI-based personalized virtual heart models (VHM) are a useful tool for reconstructing scar distribution and identifying VT circuits for planning catheter ablation procedure, an effective therapy for preventing sudden cardiac death from VT in patients with myocardial infarction. However, the MRI resolution used to reconstruct VHMs may not be sufficient to accurately detect all VT circuits, possibly leading to erroneous predictions. To predict catheter ablation targets in the arrhythmogenic substrate using VHMs reconstructed from both clinical and high-resolution 2D MRI datasets and compare the predictions. High-resolution (1.352 x 3mm) short-axis cardiac MRI were acquired by combining two subsequent clinical resolution (1.352 x 6mm) short-axis MRI from nine post-infarct patients undergoing VT ablation. The high-resolution and two clinical MRI were used to reconstruct a total of three personalized VHMs for each patient that represented the patient-specific infarct remodeling. Rapid pacing was used to assess the VT circuits and identify ablation targets in each VHM. Differences in VT inducibility and location were assessed between the high and clinical resolution VHM reconstructions, as well as between the two clinical resolution VHM reconstructions. Virtual ablations were performed to identify emergent VTs and were also compared between the VHMs for each patient. The amount of fibrotic remodeling changed by 12.6 ± 3.3% between the high-resolution and two clinical MRI VHMs for each patient, while the distribution was only moderately affected (Fig 1). The heterogeneity of the myocardium and the fractal dimension (complexity) of the scar tissue was not statistically different between the VHMs for each patient (Fig 1). VT inducibility was observed in all VHMs with an average of 2.7 [1-4] unique VT morphologies induced in each VHM. In two patients, only one clinical VHM was able to identify all the unique VT morphologies observed in the high-resolution VHM. VT exit sites in the clinical MRI VHMs were within 5mm of the exit sites observed in the high-resolution VHMs in 72.2% of cases. Virtual ablations uncovered emergent VT circuits in two of the high-resolution VHMs, compared to only one of the corresponding clinical MRI VHMs. The distribution of ablation targets required to terminate VT was statistically different in 44.4% of cases (Fig 1). VHMs reconstructed from high-resolution MRI more accurately identify VT circuits and may improve catheter ablation outcomes.