Predicting ventricular arrhythmia inducibility in ajmaline-induced brugada type I pattern: validation of the dST-Tiso interval

Abstract

Abstract Background The dST-Tiso is the interval between the onset of the coved ST-segment elevation and its termination at the isoelectric line in V1 and V2 electrocardiographic (ECG) leads during manifest Brugada (BrS) type I pattern. A dST-Tiso >300 ms was proposed as a predictor of ventricular arrythmia (VA) inducibility in patients with ajmaline-induced pattern. Purpose The aim of this study was to validate this criterion in an independent data set. Methods Consecutive patients with a BrS type I ECG pattern found after ajmaline administration underwent programmed ventricular stimulation (PVS). dST-Tiso was measured in all patients and tested as a predictor of positive VA inducibility. Results In our institution, a total of 128 patients (median age 43 years, 59% male) with drug-induced BrS Type I ECG pattern underwent PVS between January 2021 and December 2022. Thirty-two patients (25.0%) had VA inducibility that required defibrillation. Compared to non-inducible subjects, those with positive PVS were more frequently male (81% vs 51%, p=0.003), had longer PQ (165 vs. 160 ms, p=0.016) and dST-Tiso (310 vs 230 ms, p<0.001) intervals, and shorter QT interval (412 vs. 420 ms, p=0.022). The figure shows the distribution of dST-Tiso intervals for patients with not inducible and inducible VA. As a continuous variable, dST-Tiso confirmed significant association with VA inducibility with an adjusted odds ratio of 1.02 (95% CI 1.01-1.03, p<0.001) for each 1 ms increase in duration. A dST-Tiso interval >300 ms yielded a sensitivity of 75%, a specificity of 86%, positive and negative predictive values of 69% and 91%, respectively. Conclusion The validation of the estimation model based on the dST-Tiso interval >300 ms confirmed its high accuracy in predicting VA inducibility in drug-induced BrS type I pattern. This simple ECG marker might be related to the extent of the electrical substrate of the disease.Distribution of dST-Tiso intervals