Autonomic disturbance at onset of acute myocardial infarction.

Of 74 patients seen within 30 minutes of the onset of acute myocardial infarction 68 (92%) had signs of autonomic imbalance. Excessive vagal activity was evident in 41 (55%) and there was sympathetic overactivity in 27 (36%). The high incidence of sudden death in the acute phase of a coronary attack probably results from the electrical imbalance caused by autonomic disturbance. This disturbance must therefore be taken into account in any prophylactic regimen against the lethal early ventricular dysrhythmias.