FIELD: medicine. SUBSTANCE: method involves carrying out whole day monitoring of cardiac rhythm in ill children suffering from diabetes mellitus of the first type. The cardiac rhythm is analyzed during night sleep. The number of increased depression periods per night is counted. Absolute number of increased depression periods and its percentage in night sleep structure are taken into account together with morning awakening pattern. Early stage sign of autonomic cardiac neuropathy manifestation in children suffering from diabetes mellitus of the first type is considered to be increased number of absolute number of increased depression periods exceeding 5 and, when expressing it in percentage terms, exceeding 50% in night sleep structure and awakening takes place within stable rhythm period with sharp jump in heart beat rate value. EFFECT: high accuracy and reliability of the method. 2 tbl
