Abstract Body (Do not enter title and authors here): Introduction: Patients with non-ischemic cardiomyopathy (NICM), present with complex intramural ventricular tachycardia (VT) circuitry and relatively high post-ablation recurrences. Hypothesis: We hypothesize that left ventricular epicardial adipose tissue (LV-EAT) is associated with myocardial lipomatous metaplasia (LM) and post-ablation VT recurrence in NICM patients.
Methods: In this retrospective study, we quantified LV-EAT and LM in a cohort of consecutive NICM patients with cardiac contrast-enhanced CT prior to VT ablation. Cox proportional hazard regression models were used to determine the association of LV-EAT and LM with time to VT recurrence and mortality as the competing risk.
Results: Among 113 patients, 50 experienced VT recurrence during 1.7 (IQR 0.7, 4.0) years median follow-up. Patients with VT recurrence demonstrated significantly greater LV-EAT volume (median 32.9 vs. 28.2 ml, p = 0.026), greater LV-EAT thickness (median 1.0 vs. 0.9 mm, p = 0.043), and a more negative LV-EAT attenuation (median -65.1 vs. -58.4 HU, p < 0.001; Figure 1A). Univariable Cox regression demonstrated associations between all LV-EAT parameters and VT recurrence, which persisted after adjustment for heart failure and amiodarone use (adjusted hazard ratio [aHR]: 1.01 [95% CI: 1.00–1.02] per 1 ml increase of LV-EAT volume; 1.79 [1.14–2.80] per 1 mm increase of thickness; 0.94 [0.91–0.97] per 1 HU increase of attenuation value). When incorporating LM, only LV-EAT attenuation remained independently associated (aHR 0.96 per 1 HU increase, p = 0.039), alongside LM volume (aHR 1.09 per 1 ml increase, p = 0.012). Distribution analysis, using the AHA-17 segment model, demonstrated an association between lateral and inferior wall LV-EAT and VT recurrence (Figure 1B). Moderate correlation was noted between LV-EAT attenuation and LM volume (r = 0.37). Mediation analysis revealed that 10% of the effect of LM on VT recurrence was mediated by LV-EAT attenuation, while 55% of the effect of LV-EAT attenuation on VT recurrence was mediated by LM (Figure 1C).
Conclusions: LV-EAT demonstrates independent association with post-ablation VT recurrence in NICM patients while exhibiting significant statistical interaction with LM.