PJ is a sixty-seven-year-old man with a long history of stable angina. He is treated with nitroglycerin tablets as needed for chest pain. He has mild hypertension, which is well controlled by diet and an angiotensin-converting enzyme (ACE) inhibitor. PJ has noticed that his chest pain is occurring with increasing frequency and less activity is required to initiate the symptoms; however, the pain subsides quickly with rest and one or two nitroglycerin tablets.

PJ's symptoms are consistent with what diagnosis? What education would you provide to PJ?

One morning, at about 4:00 a.m., PJ is awakened from sleep with chest pain and shortness of breath. The pain is much more severe than his usual anginal pain and radiates to the jaw and the left arm. He is diaphoretic and pale. His wife calls for emergency assistance, and PJ is transported to the local emergency department. Upon admission, the electrocardiogram (ECG) shows significant ST-segment elevation.

According to the ECG findings, what is the differential diagnosis? At the time of admission, a blood sample is taken to determine whether PJ has suffered an MI. Which laboratory findings would indicate MI? Describe the pathophysiological responses occurring in the body during an MI.