Two mechanisms for mitoflash generation. Forward-mode ECT-dependent (left) and reverse-mode ATP synthase–mediated (right) mechanisms for generation of Type 1 and Type 2 mitoflashes. Middle: representative traces for Type 1 and Type 2 mitoflashes from isolated cardiac mitochondria. Scale bars: horizontal, 10s; vertical, 1 ΔF/F₀. IMM, inner mitochondrial membrane; Cx I-IV, complex I-IV; Cyt C, cytochrome C; Q, ubiquinone.