A SPATIAL SCALE FACTOR FOR ELECTROPHYSIOLOGICAL MODELS OF MYOCARDIUM

In the United States among males 20-64 years old about 1/3 of deaths a re classified as;sudden cardiac death', and 1/4 had no forewarning, no r did autopsy turn up any visible cause. The heart just switches from its normally periodic pumping to an alternative mode called `fibrillat ion' more resembling electrical turbulence. In normal tissue its mecha nism is a geometrically re-entrant mode of normal propagation. Everyth ing about this spatial pattern depends upon the magnitude of 'D', the one term with dimension involving space in the pertinent biophysical e quations. Explicit or implicit estimates in current literature span or ders of magnitude. In this article I argue from a diversity of recent experiments for a narrower range of realistic values. It has an import ant role in the spatio-temporal evolution of fibrillation and in defib rillation. (C) 1998 Elsevier Science Ltd. All rights reserved.