One thousand and twenty three cases of acute myocardial infarction within 6 hours after acute onset were divided randomly into two groups with 539 cases in the low dose group ( urokinase 22,000 IU/kg , total dose not lower than 1.2 million ) and 484 in the high dose group ( 30,000 IU/kg , total dose not more than 2.4 million ) .
