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 autonomic impairment that may persist for some time following the acute event.(1) Autonomic activity can be assessed by a variety of time- and frequency-domain techniques of heart rate variability (HRV) analysis that are sensitive and highly reproducible.(2) Patients who demonstrate a marked degree of autonomic dysfunction following myocardial infarction, manifest as reduced HRV, are at greatly increased risk of subsequent early mortality.(3,4) The administration of intravenous thrombolytic therapy reduces mortality,(5) particularly in patients who achieve successful reperfusion.(6) The mechanisms responsible for this improvement in mortality have not been well defined, but preservation of autonomic function leading to enhanced myocardial electrical stability may be important in some patients.(7) The effect of myocardial reperfusion on autonomic function has not previously been studied in detail. The aim of this study was to prospectively investigate the relation between reperfusion and early autonomic function in patients treated with thrombolysis for acute myocardial infarction using analysis of HRV, ST-segment changes, and serum myoglobin concentration.