Effect of myocardial infarction on components of fibrinolytic system.

A systematic investigation of the fibrinolytic system during the period after acute myocardial infarction in 42 patients showed a progressive reduction of fibrinolytic activity, with the longest lysis times on days 4 to 5 after the event. There is a concomitant rise in the levels of fibrinogen, plasminogen, and antiplasmin; only the latter parallels the delay in lysis. After 12 to 15 months, normal lysis times and fibrinogen levels were found in 24 patients re-examined. It is concluded that the reduced fibrinolytic activity in these patients was a transient phenomenon after myocardial infarction.