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  • Title: Why do we need supercomputers to understand the electrocardiographic T wave?
    Author: Potse M, LeBlanc AR, Vinet A.
    Journal: Anadolu Kardiyol Derg; 2007 Jul; 7 Suppl 1():123-4. PubMed ID: 17584703.
    Abstract:
    OBJECTIVE: Propagation of depolarisation and repolarisation in myocardium results from an interplay of membrane potential, transmembrane current, and intercellular current. This process can be represented mathematically with a reaction-diffusion (RD) equation. Solving RD equations for a whole heart requires a supercomputer. Therefore, earlier models used predefined action potential (AP) shapes and fixed propagation velocities. We discuss why RD models are important when T waves are studied. METHODS: We simulated propagating AP with an RD model of the human heart, which included heterogeneity of membrane properties. Computed activation times served as input to a model that used predefined AP, and to a "hybrid model" that computed AP only during repolarisation. The hybrid model was tested with different spatial resolutions. Electrocardiograms (ECGs) were computed with all three models. RESULTS: Computed QRS complexes were practically identical in all models. T waves in the fixed-AP model had 20 to 40% larger amplitudes in leads V1-V3. The hybrid model produced the same T waves as the RD model at 0.25-mm resolution, but underestimated T-wave amplitude at lower resolutions. CONCLUSION: Fixed AP waveforms in a forward ECG model lead to exaggerated T waves. Hybrid models require the same high spatial resolution as RD models.
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