Electrocardiographic morphology changes with different type of repolarization dispersions

Area of Science:

• Cardiovascular Electrophysiology
• Computational Biology
• Medical Imaging

Background:

• T-wave morphology changes are linked to ventricular repolarization heterogeneity and arrhythmia vulnerability.
• Understanding T-wave genesis is crucial for cardiac health and disease prediction.
• Key questions involve T-wave concordance with QRS, transmural repolarization dispersion, and morphology changes induced by dispersion.

Purpose of the Study:

• To investigate the relationship between cellular repolarization dispersion and T-wave morphology using a cell-to-ECG model.
• To differentiate the effects of transmural versus apical-basal repolarization dispersion on ECG.
• To analyze the impact of localized versus global dispersion patterns.

Main Methods:

• Utilized GE's cell-to-electrocardiogram (ECG) model for simulations.
• Modeled transmural dispersion by altering potassium currents (Iks, Ikr, Ito) in endocardial, M, and epicardial cells.
• Modeled apical-basal dispersion by adjusting repolarization along the ventricular axis.

Main Results:

• Global transmural dispersion prolonged QT and T-peak to T-end intervals (TpTe), inducing T-wave notches.
• Localized transmural dispersion caused T-wave changes in specific precordial leads.
• Global apical-basal dispersion altered T-wave amplitude and polarity in several leads; localized dispersion had minimal effect.

Conclusions:

• The cell-to-ECG model effectively links physiological factors to ECG morphology.
• Apical-basal repolarization dispersion contributes more to positive T waves than transmural dispersion.
• Localized transmural dispersion's ECG effects are confined to specific precordial leads.