Abstract 4337942: Prognostic Value of Unipolar and Bipolar Low Voltage Areas in Predicting Outcomes After Ventricular Tachycardia Ablation in Patients with Non-Ischemic Cardiomyopathy and Heart Failure

Background: Non-ischemic cardiomyopathy (NICM) patients with heart failure (HF) undergoing ventricular tachycardia (VT) ablation are at risk for long-term HF events. Left ventricular (LV) endocardial unipolar (Uni) and/or bipolar (Bi) low voltage areas (LVA) at ablation indicate abnormal myocardium, and their extent may predict HF events. Objective: To evaluate and compare the prognostic ability of endocardial Uni-LVA and Bi-LVA for the prediction of HF outcomes in NICM patients undergoing VT ablation. Methods: NICM and HF patients undergoing VT ablation between Jan 2020 and Dec 2023 at the Hospital of the University of Pennsylvania were included. Exclusions were ARVC, HCM, valvular disease, prior cardiac surgery. Uni-LVA was defined as <8.27mV and Bi-LVA <1.5mV during sinus/paced rhythm. Patients were followed at 6 weeks post-ablation, then at 6-month intervals. The HF outcomes included death, LVAD implant, heart transplant, or HF hospitalization. Patients were grouped into mild, moderate, and severe tertiles based on the extent of Uni-LVA and Bi-LVA. The association between tertiles and HF outcome was assessed by Cox regression, adjusted for age, sex, CKD, and LVEF. Results: A total of 137 patients with NICM and HF (mean age 62±12 years; 22.6% women) underwent VT ablation and LV endocardial voltage mapping. Of those, 129 had HFrEF (LVEF 30.5±10.8) and 8 had HFpEF (LVEF 56.5±4.4). Median Bi-LVA was 12.9% [IQR 5.4, 22.5] of the total LV endocardial surface. Bi-LVA tertiles were <8% (mild), 8-18.5% (moderate), >18.5% (severe). Median Uni-LVA was 50.1% [IQR 27.8, 76.5] of the total endocardial LV surface. Uni-LVA tertiles were <35% (mild), 35–68% (moderate), >68% (severe). HF outcomes occurred in 51 (37.2%) patients over a median follow-up of 2.6 years [IQR 1.8, 4.6]. HF outcome incidence was similar between mild Bi-LVA (24.4%, reference) and moderate Bi-LVA (30.4%, HR=0.77, 95%CI: 0.34–1.74, p=0.5), but significantly higher in severe Bi-LVA (56.5%, HR=2.8, 95%CI: 1.3–5.7, p=0.005). HF outcome incidence was 13.3% in mild Uni-LVA (reference), and significantly increased in moderate Uni-LVA (41.3%, HR=2.96, 95%CI: 1.1–7.6, p=0.02) and severe Uni-LVA (56.5%, HR=4.4, 95%CI: 1.7–10.9, p<0.001). Conclusions: The extent of endocardial LVA, particularly unipolar abnormalities, noted during VT ablation in NICM patients is a prognostic indicator for late HF outcomes. Even moderate degrees of Uni-LVA are associated with a threefold increase in the risk of late HF outcomes.