Automatic detection of characteristic points in impedance cardiogram

Estimation of stroke volume and several other cardiovascular indices using impedance cardiography requires error-free detection of the characteristic points in the impedance cardiogram. A technique for automatic detection of B, C, and X points, using R peaks in the simultaneously acquired ECG as reference, is presented. It does not require estimation of the baseline and selection of processing parameters. Use of the technique on pre-exercise and post-exercise recordings from healthy subjects and cardiac patients showed a very low detection error.