PO-05-005 SEPTAL LATE ENHANCEMENT BY CARDIAC CT IS SIGNIFICANTLY ASSOCIATED WITH VT RECURRENCE AFTER CATHETER ABLATION IN PATIENTS WITH NONISCHEMIC CARDIOMYOPATHY

Abstract

Scar substrate in patients with nonischemic cardiomyopathy (NICM) is often difficult to identify and characterize. Advances in cardiac imaging, especially using late iodine-enhanced CT (LIE-CT), allow better characterization of scars that give rise to the arrhythmia. Currently, there is limited data on clinical correlates of CT-derived scar substrates in NICM patients and outcomes. To assess relationship between scar location on LIE-CT and outcomes. Consecutive patients from 2018-2020 with non-ischemic cardiomyopathy undergoing index ventricular tachycardia (VT) radiofrequency ablation (RFA) and pre procedural cardiac CT scar modeling (InHeart models, Pessac, France) at Brigham and Women’s Hospital and Medical University of South Carolina were included. 3 patients had VT ablations at an outside facility prior to index ablation at our centers. 5 patients had CT data that could not be interpreted and were excluded. Primary endpoints were need for repeat procedure post index ablation and VT recurrence. 63 patients, mean age 63+/-12y, 90% male, mean EF 39+/-14%. 33 patients (52%) required repeat procedures. 49 patients (78%) had VT recurrence with average time to recurrence of 59 days. CT derived total scar volume was also found to be positively correlated with intrinsic QRS duration (r=0.35, p=0.005) similar to what has been shown in prior studies of cardiac MRI-detected late gadolinium enhancement. 35 patients (56%) had septal scar on cardiac CT and 42 (67%) had lateral scar (figure 1). Univariate logistic regression showed that septal scar on CT was predictive of need for repeat ablation with OR 2.9 (p=0.049; 1.0-8.4). In contrast, lateral scar did not show a statistically significant relationship (p=0.364; OR = 0.6; 0.1-1.8). Septal scar better predicted VT recurrence when compared to lateral scar, but neither were statistically significant (p=0.089; OR 2.9; 0.5-10.6 and p=0.547;OR 1.48; 0.4-5.3, respectively). In this tertiary care referral population, patients with NICM undergoing VT catheter ablation with septal LIE-CT have nearly 3-fold increased risk of VT recurrence.