Relationship between Enzymatically Estimated Infarct Size and Short‐ and Long‐term Survival after Acute Myocardial Infarction

Abstract
In 585 patients with acute myocardial infarction (AMI) and no previous MI the maximal activity of serum heat-stable lactate dehydrogenase (LD) (EC 1.1.1.27) activity was related to 1-yr and 2-yr mortality rates. All patients participated in a double-blind trial with metoprolol during the first 3 mo. after an AMI. Thereafter both groups were treated in a similar way. A strong relationship was found between LD maximum activity and the in-hospital prognosis (P < 0.001), the 1-yr survival rate (P < 0.001) and the 2-yr survival rate (P < 0.001). When the patients who were alive after primary hospitalization were analyzed as a separate group, the relationship between LD maximum activity and 1-yr and 2-yr survival rates remained (P < 0.001). In a subsample of 171 patients the maximal activity of creatine kinase (CK) (EC 2.7.3.2) and CK subunit B did not correlate either with in-hospital, 1-yr or 2-yr survival rates. When a sufficiently large number of patients are investigated, there is a strong relationship between serum enzyme maximum activity and short- and long-term survival.