Cellular physiologists are looking into the mechanisms of cardiomyocyte contraction cessation in response to ischemic injury. The left anterior descending coronary artery is ligated at time zero in an animal experiment, and changes in ATP levels within the affected myocardial cells are measured. When does the affected portion of the myocardium stop contracting on the graph?

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Eductional Objective: Cardiomyocyte contractility is lost within 60 seconds of total ischemia onset. When ischemia lasts less than 30 minutes, restoring blood flow causes reversible contractile dysfunction (myocardial stunning), with contractility gradually returning to normal over the next few hours to days. However, ischemic injury becomes irreversible after about 30 minutes of total ischemia.

Cellular Physiologists Are Looking into the Mechanisms of Cardiomyocyte Contraction