Detection of abnormal time-frequency components of the QT interval using a wavelet transformation technique

ECG repolarization abnormalities are likely to be manifested by different time-frequency (TF) components but no specific technique to detect them has yet been proposed. This study aims to describe the usefulness of a time-scale technique for the analysis of the repolarization segment components. Affected patients with Long QT Syndrome (LQTS) were used as group of patients with abnormalities in repolarization. Time-scale (TS) analysis of the repolarization interval revealed modification of the TF components with different shapes according to the leads. Comparison of ROC curves for QTc measurements and wavelet parameters demonstrates that wavelets are able to quantify T wave prolongation without the need for T endpoint determination.