Before revision:  In our model system, self-sustained patterns of excitation are generated with some frequency by random stimulation, leading us to suggest that such patterns could appear spontaneously in living tissue , either cardiac or neural, with negative consequences .
After revision:  In our model system, self-sustained patterns of excitation are generated with some frequency by random stimulation, leading us to suggest that this could happen in living tissue , either cardiac or neural, with negative consequences .