Patent ID: 8684938

Claim:
An apparatus for evaluating biological condition, which determines a symptom of a heart abnormality based on biological information that is at least one of a heartbeat interval and a pulse interval, the apparatus comprising: means for calculating an index by performing a frequency analysis on at least one of the heartbeat interval and the pulse interval, the index being indicative of the sympathetic nerve activity; means for determining whether the index is in a referential period, which is a time period in which the index satisfies a predetermined condition which shows that an amount of change in the index calculated in the index calculating means is smaller than a predetermined reference threshold value over a predetermined period; and means for determining a symptom of a ventricular fibrillation after the predetermined condition for the referential period is satisfied, the symptom being determined when the following both conditions (1) and (2) are satisfied during an evaluation period which is set after the referential period, (1) both amounts of change in the index in an increasing direction and a decreasing direction are equal to or greater than respective predetermined amount threshold values which indicate that the amount of change is greater than an amount of change in the index observed during the referential period, and (2) both rates of change in the index in the increasing direction and the decreasing direction are equal to or greater than respective predetermined rate threshold values, wherein the symptom of the ventricular fibrillation is determined when the index changes rapidly from the decreasing direction to the increasing direction in the evaluation period.