Circuit arrangement for suppression of electrical leakage currents from electrodes connected to electrocardiograph (ECG) patient by generation of atypical output signal when electrode becomes loose

摘要

Arrangement for suppression of electrical leakage currents and suppression of artifacts caused by such leakages on an ECG display when it is recorded and analyzed. For a multi-channel ECG apparatus low pass filters (TP1-TP3) and regulated amplifiers (V1-V3) are arranged between body electrodes (E1-E3) and ECG displays (S1-S3). A high frequency AC auxiliary voltage is connected via parallel high pass filters (HP2, HP3) limiters, amplifiers and time delays to the input of an AND gate (3). The output of this AND gate and the outputs of the amplifiers (V1-V3) are connected to a further AND gate (5) and a multivibrator. If one of the electrodes becomes loose or disconnected the signal to the last AND gate causes the mutlivibrator to generate an atypical signal such as a square wave signal and this causes visual and or audible alarms (L3, 8) to be triggered.