<prompt> Approximate time, at the end of which the quantity of ATP within ischemic cardiac myocytes is reduced to 10 of the original is2 minutes10 minutes20 minutes40 minutes  <response>: Metabolic changes slow as the duration of ischemia increases. Irreversibly injured myocytes exhibit a very low levels of ATP less than 10 of control; b cessation of anaerobic glycolysis; c high levels of H, AMP, INO, lactate, and alpha GP; d a greatly increased osmolar load; e mitochondrial swelling and formation of amorphous matrix densities; and f disruption of the sarcolemma. Approximately 40 minutes of time may there as the metabolic changes slow down with the decrease in ATP levels Ref internet and Robbins 9e p,27;28 