| 摘要 |
Method for determining the stroke volume of a heart comprising: attaching electrodes to the front legs or arms or head, and the hind legs of the body; connecting an alternating current source to the left pair of front legs/ arms or head, and hind legs; connecting an alternating current source to the right pair of front legs/ arms or head, and hind legs; attaching a number of electrode pairs to the thoracic skin, such that the electrodes are in contact with the skin of the thorax at predetermined positions, wherein the electrode pairs are each connected to an independent input of a data acquisition/calculation device; determining the beginning the cardiac cycle and measuring with the number of electrode pairs on the thorax the voltage at the beginning of the cardiac cycle at the predetermined positions; measuring during the cardiac cycle with the number of electrode pairs on the thorax the voltages at the predetermined positions and determining the voltage changes Vmeas (t) compared to the voltage at the beginning of the cardiac cycle; decomposing the vector of voltage changes Vmeas (t) into an atrial component a (t), and ventricular component ?(t), wherein both components are proportional to the vector of measured thorax voltages Vmeas (t) by a weight factor WA and Wvrespectively; converting the ventricular component ?(t) to a ventricular stroke volume, by multiplying the ventricular component with a constant, the constant being a predetermined volume change Vcalib divided by a ventricular component fcalib of a predetermined calibration measurement. |
