Myocardial infarct size and cardiogenic shock

The relationship between estimated infarct size and cardiogenic shock was investigated in 317 consecutively admitted patients with acute myocardial infarction (AMI). Infarct size was estimated in vivo by serum CK-MB in all patients, and at heart autopsy by histological and histochemical techniques in 23 patients who died in hospital. Although patients with cardiogenic shock (n = 31) had a larger median serum CK-MB estimated infarct size than those without cardiogenic shock (1035 U/l v. 669 U/l, P less than 0.05) there was a substantial overlap in infarct size between the two groups. Heart autopsy confirmed this finding and demonstrated that patients with small subendocardial infarcts also died from shock, especially those with severe 2 or 3 vessel disease and/or infarction fibrosis. Those with cardiogenic shock who survived and those who died from shock had a similar median infarct size, and patients who died from other cardiac causes had the same median infarct size as those who died from shock.