Decremental evoked potentials' sites characterized by low voltage and consistent electrograms amplitude in patients with post-infarction ventricular tachycardia.

backgroundFunctional substrate mapping during infarct-related ventricular tachycardia ablation is a crucial step to identify critical isthmus locations. The use of basic voltage map metrics to predict the location of these critical sites might alleviate the challenges of performing full left ventricle functional mapping and might facilitate success and efficiency of infarct-related VT ablation.

objectiveThis study aims to characterize regional voltage metrics at sites showing Decremental Evoked Potentials (DEEP) during functional mapping and also aims to detect whether these voltage metrics can potentially predict DEEP sites. METHODOLOGY: This is a retrospective study wherein 14 patients with infarct-related VT underwent endocardial ablation in our institution between January 2021 and March 2023. High-density omnipolar voltage and functional substrate mapping maps were exported and merged with a cardiac tomography (CT)-derived left ventricular (LV) model. Subsequently these models were segmented into 17 segments (per patient) for further analysis. For each segment values of voltage median, voltage interquartile range (IQR), and presence of DEEP response during functional mapping were acquired. The difference in these voltage metrics between DEEP + and DEEP- segments was analyzed. Furthermore, the ability of these metrics to predict DEEP status was explored.

resultsA total of 233 LV segments were included. 168 segments were labelled as DEEP negative (DEEP-). The DEEP+ segments exhibited lower voltage than DEEP – segments (respectively 0.94 mV versus 1.95 mV, p < 0.001) and lower voltage interquartile range (IQR) (respectively 1.01 mV versus 2.66 mV, p < 0.001). Furthermore, each 1-mV increase in any segment voltage median was associated with a 53% reduction in the odds of DEEP+ (OR = 0.47, 95% CI [0.33, 0.66], p < 0.001), and a 1-mV increase in voltage IQR was associated with a 45% decrease (OR = 0.55, 95% CI [0.42, 0.72], p < 0.001). The Receiver Operating Characteristic (ROC) analysis revealed that the AUC for voltage median was 0.70 and for voltage IQR was 0.71. The optimal thresholds for predicting DEEP+ sites were voltage median < 1.53 mV and voltage IQR < 2.55 mV.

conclusionsLeft ventricular regions harboring critical electrograms displaying a DEEP+ response tend to have lower regional voltage median and lower voltage IQR.