Impedance cardiography

Impedance cardiography (ICG; also called electrical impedance plethysmography, EIP, or thoracic electrical bioimpedance, TEB) is a non-invasive technology measuring total electrical conductivity of the thorax and its changes over time. ICG continuously processes a number of cardiodynamic parameters, such as stroke volume (SV), heart rate (HR), cardiac output (CO), ventricular ejection time (VET), and pre-ejection period; it then detects the impedance changes caused by a high-frequency, low magnitude current flowing through the thorax between additional two pairs of electrodes located outside of the measured segment. The sensing electrodes also detect the ECG signal, which is used as a timing clock of the system.