Raja, Deep ChandhShroff, JenishNair, AnugrahAbhilash, Sreevilasam P.Tuan, Lukah Q.Mehta, AbhinavAbhayaratna, Walter P.Sanders, PrashanthanFrankel, David S.Marchlinski, Francis E.Pathak, Rajeev Kumar2025-06-292025-06-291547-5271PubMed:38636932ORCID:/0000-0001-7373-8231/work/185260668ORCID:/0000-0002-7391-6867/work/187319042http://www.scopus.com/inward/record.url?scp=85194087856&partnerID=8YFLogxKhttps://hdl.handle.net/1885/733765502Background: Endocardial electrogram (EGM) characteristics in nonischemic cardiomyopathy (NICM) have not been explored adequately for prognostication.  Objective: We aimed to study correlation of bipolar and unipolar EGM characteristics with left ventricular ejection fraction (LVEF) and ventricular tachycardia (VT) in NICM.  Methods: Electroanatomic mapping of the left ventricle was performed. EGM characteristics were correlated with LVEF. Differences between groups with and without VT and predictors of VT were studied.  Results: In 43 patients, unipolar EGM variables had better correlation with baseline LVEF than bipolar EGM variables: unipolar voltage (r = +0.36), peak negative unipolar voltage (r = −0.42), peak positive unipolar voltage (r = +0.38), and percentage area of unipolar low-voltage zone (LVZ; r = −0.41). Global mean unipolar voltage (hazard ratio [HR], 0.4; 95% confidence interval [CI], 0.2–0.8), extent of unipolar LVZ (HR, 1.6; 95% CI, 1.1–2.3), and percentage area of unipolar LVZ (HR, 1.6; 95% CI, 1.1–2.3) were significant predictors of VT. For classification of patients with VT, extent of unipolar LVZ had an area under the curve of 0.82 (95% CI, 0.69–0.95; P < .001), and percentage area of unipolar LVZ had an area under the curve of 0.83 (95% CI, 0.71–0.96; P = .01). Cutoff of >3 segments for extent of unipolar LVZ had the best diagnostic accuracy (sensitivity, 90%; specificity, 67%) and cutoff of 33% for percentage area of unipolar LVZ had the best diagnostic accuracy (sensitivity, 95%; specificity, 60%) for VT.  Conclusion: In NICM, extent and percentage area of unipolar LVZs are significant predictors of VT. Cutoffs of >3 segments of unipolar LVZ and >33% area of unipolar LVZ have good diagnostic accuracies for association with VT.We acknowledge support extended by cardiac physiologists at the Canberra Heart Rhythm Centre for collection of data, Pawel Kuklik for segmentation analysis of the electroanatomic mapping data, and Kieran King for technical support with CARTO. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. All authors attest they meet the current ICMJE criteria for authorship.8en© 2024 The Author(s)Bipolar voltageElectroanatomic mappingLow-voltage zoneNonischemic cardiomyopathyUnipolar voltageVentricular tachycardia2024-04-1610.1016/j.hrthm.2024.04.06585194087856