Levels Building the Virtual Heart

Extension to the level of the whole organ came in collaboration with the University of Auckland, where Peter Hunter, Bruce Smaill, and their colleagues in bioengineering and physiology constructed the first anatomically detailed models of a whole ventricle, including mechanics. These models include fiber orientations and sheet structure [31, 32], and are used to incorporate the cellular models in an attempt to reconstruct the electrical and mechanical behavior of the whole organ. 

This work includes simulation of the activation wave front [7, 33, 34]. This is heavily influenced by cardiac ultra-structure, with preferential conduction along the fiber-sheet axes and the result corresponds well with that obtained from multielectrode recording from dog hearts in situ. Accurate reconstruction of the depolar- 

Work at the level of the whole ventricle is progressing rapidly as the necessary computing power becomes available (Fig. 9.7). This includes reconstructing some of the arrhythmic processes occurring during ischemia [40], the mechanisms of breakdown into fibrillation [41], modeling of the coronary circulation [34], and the mechanisms of defibrillation [37]. 

These models have been used to study the mechanisms of arrhythmogenesis [43, 44] and to study the actions of drugs such as d-sotalol on propagation [43]. 

1 Weidmann, S. Effect of current flow on the membrane potential of cardiac muscle. Journal of Physiology 1951,115 227-236. 

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