Apparatus for evaluating biological condition, method for the same, and computer program product
First Claim
1. 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.
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Abstract
A biological condition evaluation apparatus determines a symptom of a heart abnormality based on at least one index calculated from a heartbeat interval and/or a pulse interval. The apparatus determines whether it is in a referential period where an amount of change in the index is comparatively small. The apparatus determines whether a plurality of conditions are satisfied or not in an evaluation period set after the referential period. One condition is that an amount of change in the index in the evaluation period is greater than that observed during the referential period. Another condition is that a rate of change in the index is equal to or greater than a predetermined threshold value. The apparatus determines that there is a symptom of a heart abnormality, when both the conditions are satisfied.
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Citations
20 Claims
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1. 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:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method 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 method comprising the steps of:
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calculating an index with a microcomputer 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; determining, with the microcomputer, 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 step is smaller than a predetermined reference threshold value over a predetermined period; and determining, with the microcomputer, 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 abnormality 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. - View Dependent Claims (18, 19, 20)
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Specification