Hybrid qrs detection circuit based on dynamic reconfigurable field programmable analog array

In many medical applications it is important to detect the QRS complex in the electrocardiogram (ECG) waveform with possibly low time delay. Traditional software detectors of the QRS complex implement algorithms usually based on cascades of digital filters introduce delays up to parts of a second. Hardware QRS detectors fulfill the low delay requirements, but have worse adaptive features for the changing ECG shape. In this paper a new approach to QRS detection is presented. The proposed detector is based on a Field Programmable Analog Array (FPAA). The most interesting feature of the FPAA is the dynamic reconfigurability. This solution makes it possible to modify the parameters of particular blocks of the detector or even the whole structure during runtime, without any changes in hardware and disturbance of the system functionality. The prototype QRS detector was built using AN221E04 circuit from the Anadigm company. The reconfiguration data are calculated by the AD7020 microcontroller and downloaded to the FPAA after each QRS detection.