Single Reference Segmentation to Estimate T-Wave Alternans.

T-Wave Alternans (TWA) are an indicator of sudden cardiac death risk, and they measure the differences between consecutive T-waves in Electrocardiogram (ECG) studies. In this work, we used ECG Imaging (ECGI) data to scrutinize the spatial distribution of alternans along the torso and epicardium. ECGI signals were obtained from the torso of eight patients suffering from Long QT syndrome and from three control subjects, and epicardial signals were estimated through the inverse problem of ECG. We introduced a new method for segmenting T-waves, called the Single Reference Segmentation (SRS), and we analyzed its performance by estimating TWA and comparing it to the atomic segmentation method, consisting of performing the alignment of each signal in isolation. Our results showed that SRS improves the quality of TWA estimations, which could provide clinically useful representations of the spatial-temporal distribution of TWA using ECGI data.