Sudden Cardiac Death Prediction in Chagas Heart Disease Patients from ECG-derived Biomarkers of Ventricular Restitution

Sudden cardiac death (SCD) remains an important cause of mortality in patients with Chagas heart disease (ChHD).The aim of this study is to compare the SCD predictive value of ECG-derived indices of ventricular restitution, the response to heart rate changes of the QT ( QT ) and T-peak-to-T-end (Tpe, T pe ) intervals, the T-wave morphology restitution index (T M R) and Tpe morphology restitution index (T peM R) in a population with ChHD.We derived these indices from Holter ECG recordings from 140 patients with ChHD and evaluated their association with SCD.SCD victims showed significantly higher values of T pe and T peM R compared to the rest of patients (p <.001).Multivariate Cox analyses after adjusting for the Rassi score showed that individuals with T pe and T peM R values greater than 0.036 and 0.021 had a hazard ratio (HR) of 2.93 (p <.001) and 2.02 (p=0.023),respectively.In conclusion, T pe and T peM R, both quantifying end-stage ventricular restitution, are strongly and independently associated with SCD.The lack of predictive value of QT and T M R might be associated to other effect of ChHD on the early stages of ventricular repolarization unrelated to SCD.