BURSTING CALCIUM ROTORS IN CULTURED CARDIAC MYOCYTE MONOLAYERS

Rotating waves (rotors) of cellular activity were observed in nonconfl uent cultures of embryonic chick heart cells by using a macroscopic im aging system that detected fluorescence from intracellular Ca2+. Unlik e previous observations of rotors or spiral waves in other systems, th e rotors did not persist but exhibited a repetitive pattern of spontan eous onset and offset leading to a bursting rhythm. Similar dynamics w ere observed in a cellular automaton model of excitable media that inc orporates spontaneous initiation of activity, and a decrease of excita bility as a consequence of rapid activity (fatigue). These results pro vide a mechanism for bursting dynamics in normal and pathological biol ogical processes.