Methods for intracardiac electrogram compression suitable with implantable devices

Studies methods for intracardiac electrogram compression that are suitable for implementation in implantable devices. The algorithms are based on piecewise linear approximation (PLA) methods and beat detection (the peak method). Intracardiac electrograms were obtained, from the right atrium and ventricle, during electrophysiological studies. The total atrial set consists of 5060 s of bipolar recordings and 680 s of unipolar electrograms; the ventricular data set contains 1210 s of bipolar and 480 s of unipolar signals. The peak method clearly performs better than the others to compress bipolar signals, while PLA methods are needed in order to have reliably compressed unipolar data. Performances over the whole bipolar database (including atrial and ventricular sets) reached an average compression ratio (CR) of 7.6, while first-order piecewise linear approximation on unipolar electrograms reached CR=6.6. These preliminary results show that time consumption can be reduced suitably with real-time compression for implantable devices. The ability to compress and store intracardiac electrograms in implantable devices allows detailed verification of appropriate intervention of the device and it might open up new perspectives in the study of the mechanisms involved in the onset of malignant tachyarrhythmias.