You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Irreversible injury in myocardium occurs at ? and explain in detail?
Ans. is 'b' i.e., 30 minutes The metabolic rate of the hea is high, and its stores of substrate are low. So, hea is critically dependent on a continuous supply of oxygen and nutrients. Ischemia of myocardium induces profound functional, biochemical and morphological consequences. Myocardial function is more sensitive to isc_hemia (loss of contractility occurs within 60 seconds) than myocardial structure (irreversible injury occurs in 20-40 minutes, thus myocardial necrosis begins at approximately 30 minutes after coronary occlusion. Key events in ischemic cardiac myocytes Feature Time Onset of ATP depletion Seconds Loss of contractility < 2 minutes ATP reduced to 50% 10 minutes ATP reduced to 10% 40 minutes Irrversible injury 2040 min Microvascular injury > 1 hr