Importance of peak enzyme level and reinfarction while attempting to intervene myocardial infarction process

Isosorbide dinitrate (ISDN) was tried in 27 patients, of which 4 patients with evidence of reinfarction were excluded in the course of the study, with acute myocardial infarction, with the aim of reduction of enzymatically estimated infarction size. The drug apparently seemed useless, when overall effects of the therapy was looked into. But in the group, where drug was administered before the occurrence of peak enzyme level (PEL), ISDN could reduce infarction size by 22.95% (p less than 0.01). Similarly when all the 12 cases of re-elevation of enzyme level (suggesting reinfarction) were excluded, the drug was found to reduce infarction size by 21.14% (p less than 0.01). Time of onset of therapy with respect to PEL and occurrence of reinfarction seemed to be important governing factors regulating the efficacy of drug therapy.