pH paradox ischemia acidosis, disorder of function and metbolism on cell severe ri pH paradox calcium paradox pre-perfuse rat heart with no calcium perfusion for 2min perfuse calcium perfusion, cell release enzyme myofibril over-constract, electron signals abnormal, calcium paradoxpH paradox ischemia acidosis , disorder of function and metbolism on cell severe IRI pH paradox calcium paradox pre-perfuse rat heart with no calcium perfusion for 2min perfuse calcium perfusion, cell release enzyme myofibril over-constract, electron signals abnormal, calcium paradox