Calcium waves initiating from the anomalous subdiffusive calcium sparks

The objective of the study is to investigate the propagation of Ca2+ waves in full-width cardiac myocytes and carry out sensitivity analysis to study the effects of various physiological parameters on global Ca2+ waves. Based on the anomalous subdiffusion of Ca2+ sparks, a mathematical model was proposed to characterize the Ca2+ waves. The computed results were in agreement with the experimental measurements using confocal microscopy. This model includes variables of current through the Ca2+ release unit (CRU; I-CRU), duration of current flow through CRU (T-open), Ca2+ sensitivity parameter (K), the longitudinal and transverse spatial separation of CRUs (l(x) and l(y), where x denotes longitudinal direction (x-axis) and y denotes transverse direction (y-axis)) and Ca2+ diffusion coefficients (D-x, D-y). The spatio-temporal mechanism of the anomalous Ca2+ sparks led to results that were different from those based on Fick's law. The major findings were reported as: I-CRU affected the dynamic properties of Ca2+ waves more significantly than T-open; the effect of K on the properties of Ca2+ waves was negligible; l(y) affected the amplitude significantly, but l(x) affected the longitudinal velocity significantly; in turn, the limitation and significance of the study are discussed.