Early reactivation of ischaemia after abrupt discontinuation of heparin in acute myocardial infarction.

Intravenous heparin after thrombolytic therapy for acute myocardial infarction is an effective, widely used treatment. Six cases of acute myocardial infarction are reported with early disease reactivation following the abrupt discontinuation of heparin infusion three days after alteplase thrombolysis and concomitant aspirin therapy. Immediate reinfusion of heparin resulted in regression of symptomatic ischaemia in all six patients. The activated partial thromboplastin time values, determined four hours before the discontinuation of heparin therapy, were within the therapeutic range in five of the six patients, and no difference was found in the values obtained one hour after the reinfusion of heparin (P = 0.065).