T-Wave Changes Due to Cardiac Deformation Are Dependent on the Temporal Relationship Between Repolarization and Diastolic Phase.

Over the last years computational modelling of the ECG has seen a rise in popularity. In general, the ECG is calculated based on myocyte membrane voltages and so called forward calculating of the potentials on the body surface. In nearly all cases though the deformation of the heart is neglected. This becomes a more prominent problem when looking at the T-wave. Within the ECG the T-wave shows the repolarization of the ventricles back to their resting potential. This can align with different phases of the contraction cycle, depending on action potential duration and temporal delay between electrical excitation and mechanical response. In this study we present a finite element, fully coupled electro-mechanical model, which is deforming within a torso geometry. By artificially shifting the membrane potentials in time, we can assess how different phases of the contraction cycle affect T-wave properties. In contrast to previous studies our results show little effect of deformation on T-wave amplitude, and only minor morphology changes, delaying the peak of the T-wave. By artificially shifting the potentials to a more contracted state these effects were amplified.