Progressive nature of myocardial injury in selected patients with cardiogenic shock.

To determine whether the extensive myocardial injury associated with cardiogenic shock in some patients results from a progressive rather than a discrete massive insult, a study was made of 15 selected patients who had cardiogenic shock within 48 hours of admission, 5 patients with hypovolemic shock without myocardial infarction and 11 patients with myocardial infarction without shock. Peak plasma MB creatine kinase (CK) activity was significantly higher in the seven patients with cardiogenic shock associated with initial infarction (213 international units [IU]/liter) than in patients with shock and previous infarction (98 IU/liter) and in patients with uncomplicated myocardial infarction (125 IU/liter). A prolonged time to peak MB CK activity (averaging 26 hours) and a plateau of elevated MB CK activity were seen in patients with shock associated with initial infarction. Because shock itself did not slow the rate of apparent MB CK disappearance, results obtained suggest that cardiogenic shock associated with initial infarction in selected patients results from progressive myocardial damage underlying continuing release of MB CK into the circulation. The findings are compatible with the concept that, in these patients, cardiogenic shock reflects a vicious cycle of spreading myocardial injury, progressive compromise of cardiac function, exacerbation of ischemia and perpetuation of myocardial damage.