Abstract: 280 cases of serious epidemic encephalitis have been treated in our hospital. Amongthem there were 97 cases having complication of cardiac failure. We found that the more serious of thepatients' condition the higher incidence of the cardiac failure. The patients complicated DIC and RDS wereliable to the heat failure; the vascular acting drug, phentolame, 654- 2 could reduce morbidity of the heatfailure. Incidence of the heat failure in children was highter than 4hat in adult. The cases accompanied persistent high fever, frequent convulsion and sputum suffocated were possible t0 increase morbidity of theheat failure. The patients happening to the heat failure were treated with the cardiotonic as soon as ifossible, which can reduce the mortality obviously.