An endocardial unipolar voltage cutoff of 3.9 mV identified epicardial bipolar voltage <1.50 mV with an AUC of 0.75, 60% sensitivity, and 79% specificity.
Observational (n=33)
What is the optimal endocardial unipolar voltage cutoff for identifying epicardial right ventricular scar in patients with scar-related ventricular tachycardia?
An endocardial unipolar voltage cutoff of 3.9 mV improves diagnostic accuracy for identifying epicardial right ventricular scar at sites with <1.0 mm fat.
Effect estimate: AUC 0.75
BACKGROUND: Low endocardial unipolar voltage (UV) at sites with normal bipolar voltage (BV) may indicate epicardial scar. Currently applied UV cutoff values are based on studies that lacked epicardial fat information. This study aimed to define endocardial UV cutoff values using computed tomography-derived fat information and to analyze their clinical value for right ventricular substrate delineation. METHODS AND RESULTS: Thirty-three patients (50±14 years; 79% men) underwent combined endocardial-epicardial right ventricular electroanatomical mapping and ablation of right ventricular scar-related ventricular tachycardia with computed tomographic image integration, including computed tomography-derived fat thickness. Of 6889 endocardial-epicardial mapping point pairs, 547 (8%) pairs with distance 1.50 mV, the optimal endocardial UV cutoff for identification of epicardial BV <1.50 mV was 3.9 mV (area under the curve, 0.75; sensitivity, 60%; specificity, 79%) and cutoff for identification of abnormal epicardial electrogram was 3.7 mV (area under the curve, 0.88; sensitivity, 100%; specificity, 67%). The majority of abnormal electrograms (130 of 151) were associated with transmural scar. Eighty-six percent of abnormal epicardial electrograms had corresponding endocardial sites with BV <1.50 mV, and the remaining could be identified by corresponding low endocardial UV <3.7 mV. CONCLUSIONS: For identification of epicardial right ventricular scar, an endocardial UV cutoff value of 3.9 mV is more accurate than previously reported cutoff values. Although the majority of epicardial abnormal electrograms are associated with transmural scar with low endocardial BV, the additional use of endocardial UV at normal BV sites improves the diagnostic accuracy resulting in identification of all epicardial abnormal electrograms at sites with <1.0 mm fat.
Venlet et al. (2017) conducted an observational in Right ventricular scar-related ventricular tachycardia (n=33). Endocardial unipolar voltage mapping was evaluated on Identification of epicardial bipolar voltage <1.50 mV at sites with endocardial bipolar voltage >1.50 mV (AUC 0.75). An endocardial unipolar voltage cutoff of 3.9 mV identified epicardial bipolar voltage <1.50 mV with an AUC of 0.75, 60% sensitivity, and 79% specificity.