Evaluation of algorithms for real-time ECG data compression

After having analyzed the recent electrocardiogram (ECG) data compression techniques, three algorithms (TRIM, AZTEC-VT, SAPA-2), which can be implemented on a real-time ambulatory ECG recording system, have been tested. The most suitable methods for reconstruction of the compressed signal have also been investigated. Particular attention has been paid to the definition of the performance indexes. Considerations on the filtering power of the algorithms have been made, using an ECG signal synthesizer. The results show that while TRIM and SAPA-2 may be considered at the same level, AZTEC-VT does not achieve similar performance. It is convenient to give a preference to SAPA-2, for online processing, because TRIM requires the input of four dimensional parameters in order to adapt the algorithm to the signal, while SAPA-2 requires only one input parameter. It is concluded that compression algorithms, considering processing time, compression ratio and the error introduced, allow performance that is adequate for real-time data compression in new generation Holter systems