T wave shape changes with heart rate: a computer model analysis

The electrocardiogram T wave shape is known to change with the heart rate, but the cause is little understood. In this work, using a computer model of the left ventricle repolarisation, we investigated the T wave shape changes and proposed an explanation for this behaviour We used a computer model of left ventricle repolarisation to simulate the 12-lead ECG T waves. We defined a dispersion/duration ratio (Disp/APRD) as the maximum dispersion of repolarisation divided by the action potential repolarisation phase duration. The Disp/APRD is a measure of the heart rate in the model. We show that for increasing value of the Disp/APRD the T waves change in shape becoming more symmetrical while the T wave start-to-peak time interval shortens. We verified these results experimentally by recording the ECG on an healthy subject for two different heart rates (75 bpm and 130 bpm). We showed that our model predictions are confirmed by these preliminary experimental findings. The results from our model show, we believe for the first time, how the shape of the T wave changes with the heart rate and propose an explanation for this behaviour in terms of the Disp/APRD ratio. This work may have strong implications for improving the diagnosis of heart diseases using common clinical tests such as the exercise electrocardiography