PRESENTATION OF AUTONOMIC FUNCTION FOLLOWING SUCCESSFUL REPERFUSION WITH STREPTOKINASE WITHIN 12 HOURS OF THE ONSET OF ACUTE MYOCARDIAL-INFARCTION

Acute myocardial infarction is associated with variable degrees of aut onomic impairment that may persist for some time following the acute e vent.(1) Autonomic activity can be assessed by a variety of time- and frequency-domain techniques of heart rate variability (HRV) analysis t hat are sensitive and highly reproducible.(2) Patients who demonstrate a marked degree of autonomic dysfunction following myocardial infarct ion, manifest as reduced HRV, are at greatly increased risk of subsequ ent early mortality.(3,4) The administration of intravenous thrombolyt ic therapy reduces mortality,(5) particularly in patients who achieve successful reperfusion.(6) The mechanisms responsible for this improve ment in mortality have not been well defined, but preservation of auto nomic function leading to enhanced myocardial electrical stability may be important in some patients.(7) The effect of myocardial reperfusio n on autonomic function has not previously been studied in detail. The aim of this study was to prospectively investigate the relation betwe en reperfusion and early autonomic function in patients treated with t hrombolysis for acute myocardial infarction using analysis of HRV, ST- segment changes, and serum myoglobin concentration.