| 摘要 |
PURPOSE: To measure a cardiac competence factor index by calculating the product of the measured left ventricle pressure and left ventricle capacity as a function of time, judging the time derivative of the product, and judging the gradient of the time derivative when it rises. CONSTITUTION: Measuring means for the pressure of the left ventricle measures the time of arrival of a cardiac pressure pulse at a given part at a plurality of pressure values, particularly one set of optimized pressure values, thereby calculating the product of the left ventricle pressure and the left ventricle capacity as a function of time. In this case, the product of the corresponding pressure and capacity value is calculated at a plurality of points through the contraction period, typically at thirty-two points. The time derivative of the product is typically calculated by use of the quadratic center differential method, whereby points on a cardiac ability curve are created. Then a CPU makes calculations from cardiac ability curve values; i.e., a linear regressive line conforms to the points on the ability curve from the start of the contraction period to its maximum value. Some data points whose values are separated from the linear regressive line by twice a standard deviation or more are excluded to calculate a new regressive line, whose gradient is used as a final CPI value. |
