Irreversible injury in myocardium occurs at -: (A) 2 minutes, (B) 30 minutes, (C) 2 hours, (D) 5 hours
Answer is B. Ans-Bo Myocardial function is more sensitive to ischemia(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.FeatureTimeo Onset of ATP depletiono Loss of contractilityo ATP reduced to 50%o ATP reduced to 10%o Irrversible injuryo Microvascular injurySeconds< 2 minutes10 minutes40 minutes20-40 min> 1 hr