Total internal reflection fluorescence microscopy study of spiral Ca2+ waves in single heart cell

Spiral wave phenomena exist in many scales of nature and have attracted the attention of scientists from different fields. Although much work has been done on qualitative analysis of spiral waves, the mechanism of spiral waves' spontaneous formation and termination in living systems is still not clear. Here, by using total internal reflection fluorescence microscopy, we show the spiral waves of calcium signals in single rat cardiac myocytes and the simulation of the waves comprising calcium sparks. The mechanism of the formation and termination of spiral waves is attributable to the calcium release channels' refractory resulting from their stochastic release. We suggest that this mechanism can be adapted to other living systems.