Somayeh Iranpak - Department of Computer Engineering, Islamic Azad University, Sabzevar , Iran
Seyed Mehdi Shahidi - Department of Computer Engineering, Islamic Azad University, Sabzevar , Iran
Mohammd Pourmahmoud hesar - Department of Computer Engineering, Islamic Azad University, Sabzevar , Iran

Electrocardiograph is a device for recording electrical cardiac changes. The curves recorded by this instrument are called electrocardiograms which play an important role in diagnosing further heart disease. Since the collected data of the electrocardiogram is large, compression is compulsory. Compression efficiently records and retrieves data in medical databases. Although many compression algorithms have already taken some successful steps in compression, still the need for algorithms with better compression ratio and less data loss in the regenerated signal is felt. This study compares the different approaches of electrocardiogram signal compression (direct time domain, domain transformation, parameter extraction and two-dimensional transformation) and various methods for applying these approaches (Milestone, Delta encoding, wavelet, etc.) using different performance and efficiency criteria (compression ratio, quality score, etc.). Finally, the different methods will be analyzed and the main challenge in this area will be discussed.

electrocardiogram , signal compression , parameter extraction , direct transformation , domain transformation , two -dimensional transformation .