DSP based real-time rate detection with cycle length and morphology monitoring

A DSP-based real-time rate detection algorithm developed in a LabVIEW system is described. The algorithm detects atrium and ventricle depolarization as shown in their intracardiac or surface electrical recording. By using proper bandpass filtering, low value clipping, peak detection of rectified signal or its first derivative, adaptive threshold, refractory blanking, a reliable rate counting can be achieved. In addition to the rate counting, peak values and locations are used for reconstruction of waveform for morphology monitoring. Beat-to-beat cycle length and depolarization width can be also easily obtained and displayed in time domain and in a return map. A scatter diagram is used to display the relationship between amplitudes of atrium electrogram and ventricle electrogram. Cross correlation is used to monitoring morphology changes. From the results, the algorithm appears to be useful for real time monitoring of electrophysiology studies and for further development of sensing algorithms for detection and classification of tachycardias in implantable and external antitachycardia devices