Hybrid system of ECG signal acquisition and QRS complexes detection for special medical devices synchronization

Some medical devices such as mechanical circulatory support systems and defibrillators require synchronization with the appropriate phase of the cardiac cycle of the patient. This paper presents a description of the electrocardiographic (ECG) signal amplifier and QRS detector designed for use with such devices. The detector system was built using a programmable analog array AN231E04 and the ECG amplifier with an analog-digital (A/D) converter based on a programmable circuit (front-end) ADS129x. By using the programmable elements and exploiting the potential of dynamic analog matrix reconfiguration, the presented detector achieved the desired features, such as low latency of QRS detection, automatic gain control and the ability to change the time constant by software. High-resolution of the A/D converter in the ADS1298x and the possibility of programming the gain of the amplifier allow the acquisition of the ECG signal acquired from different types of electrodes: disposable standard, epicardial or endocavitary. The tests of the prototype system proved that it is highly effective for the detection of QRS complexes in ECG waveforms recorded from all kinds of electrodes.