Mechanism of Early Contractile Failure During Ischemia

摘要: The basis of early ischemic contractile failure was investigated in perfused ferret hearts. Isovolumic left ventricular developed pressure fell by more than 50% within 30 s the onset total global ischemia and reached zero 5 min. Monophasic action potential recordings revealed no decrease excitability during this period. Phosphorus nuclear magnetic resonance spectra obtained at 30-s resolution showed significant changes inorganic phosphate or phosphocreatine first ischemia. Intracellular pH (pHi) ATP changed even slowly; therefore, none these metabolites could account for rapid fall force. To gauge contribution intravascular pressure, we compared ordinary aortic flow occlusion with tissue-level induced massive coronary microembolization level precapillary arterioles. Functional depression significantly slowly microembolized hearts, despite accumulation protons comparable that After microembolization, time course functional reflected much closely concomitant pHi changes. Thus, our results provide novel evidence supporting importance vascular collapse mechanism failure.