Apparatus and method for automatic lead selection in electrocardiography

摘要

An ECG electrode impedance measuring approach is utilized which can determine, simultaneously, the condition of all electrodes in a three or five lead ECG monitoring configuration. A CPU automatically selects an ECG lead configuration in which all electrodes are attached to the patient and are below an impedance threshold. If the CPU cannot select a good ECG lead configuration, then the CPU signals a total lead failure. Electrode impedance is determined by passing a small DC current through each active electrode and the current is returned via the reference electrode. A comparator tests the resultant offset voltage induced between each active electrode and the reference. If the offset voltage exceeds a fixed threshold, then a flag is set and transferred to the CPU. The CPU can change the ECG lead configuration by issuing commands to an electrode lead switching network. The CPU software tests each lead configuration in a logical sequence to find one in which all the necessary electrodes are functional and a good quality ECG waveform can be processed and displayed. If a useable lead configuration cannot be found, then an alarm is activated to alert the operator to check all electrodes.