Diagnostic and Prognostic Insights into Cardiac Repolarization from an Architectural T Wave Analysis Program

Aims:

Noninvasive characterization of cardiac repolarization (CR) abnormalities is limited in current practice. In particular, the surface ECG (principally the QT interval) is often used as a surrogate for CR however it reduces the complex repolarization process to a single value. We therefore aimed to develop and test a novel T wave analysis program that characterizes CR beyond currently available ECG metrics.

Methods and Results:

We developed a software package in MATLAB to facilitate T-wave analysis. The software provides automatic 12-lead ECG T wave feature detection and extraction (Figure 1). We tested this program in a cohort of Long QT Syndrome [LQTS] patients (n=420) and a cohort of patients who experienced drug-induced torsade de pointes (TdP) (n= 13). In patients who experienced TdP, we demonstrated that the T wave right slope correlated strongly with TdP risk. In LQTS patients, a combination of T wave features was able to distinguish patients with either LQT1/LQT2 from healthy matched controls [Tpeak–Tend interval, T wave left slope, and T wave center of gravity x axis (last 25% of the T wave)], including those with a concealed phenotype (normal resting QTc). T wave analysis has also provided prognostic information identifying those at risk of future LQTS arrhythmic events (Left slope of T wave in lead V6 and T wave center of gravity x axis (last 25% of wave) in lead I). Further, it could differentiate acquired from drug-induced QT prolongation (T wave right slope, T-peak-Tend interval, T wave center of gravity on the x axis).

Conclusions:

Our novel architectural T wave analysis program can detect abnormalities in CR from the surface ECG across a spectrum of cardiac repolarization abnormalities. It adds important diagnostic and prognostic power to the standard 12-lead ECG.