Dispersion of repolarisation and the T wave: a computer model

A simple mathematical model of repolarisation of the left ventricle is presented. The T wave on the surface electrocardiogram is simulated. The model is applied to the study of increased dispersion of repolarisation that has been shown to be a substrate for fatal arrhythmias. Results from the model show that symmetrical and tall pathological T waves are a product of increased dispersion of repolarisation in the left ventricle. The end of the simulated T waves is the same in all 12 leads, suggesting that QT dispersion (defined as the differences of QT intervals in the 12 standard leads) is not a good measure of dispersion of repolarisation. The symmetry ratio, (SR), which measures the symmetry of the T wave, is shown to be a good candidate. The model predicts a value of SR close to 1.5 for small values of dispersion. This result is in agreement with the mean value of the symmetry ratio in normal subjects as reported in literature. For increasing values of dispersion, SR from. The model decreases towards value close to 1, demonstrating the source of the more symmetrical T waves in these patients