Predicting ventricular arrhythmia inducibility in ajmaline‐induced Brugada type I pattern: Validation of the dST‐Tiso interval.

Introduction: The dST‐Tiso is a newly proposed electrocardiographic (ECG) marker during Brugada (BrS) type I pattern, that predicts the likelihood of ventricular arrhythmia (VA) inducibility in patients with ajmaline‐induced pattern. The objective of this study was to validate the effectiveness of this criterion using an independent data set. Methods: Consecutive patients exhibiting a BrS type I ECG pattern following ajmaline administration underwent programmed ventricular stimulation (PVS). dST‐Tiso interval was measured in all patients and tested as a predictor for positive VA inducibility. Results: Among 128 patients (median age 43 years, 59% male) with drug‐induced BrS type I ECG pattern who underwent PVS, 32 (25.0%) had VA inducibility that required defibrillation. Compared to noninducible subjects, those with positive PVS were more commonly 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). When treated as a continuous variable, dST‐Tiso confirmed significant association with VA inducibility, with an adjusted odds ratio of 1.02 (95% confidence interval: 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%, and positive and negative predictive values of 69% and 91%, respectively. Conclusion: The validation of the 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 straightforward ECG marker might be linked to the extent of the electrical substrate of the disease. [ABSTRACT FROM AUTHOR]

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