MULTIWAVE is a multiresolution wavelet-based algorithm for data compression of ECG signals. ECG signals are decomposed into coarse and fine components. Decomposition is carried out by a pyramidal algorithm that analyzes the signal at successive scales by convolution with an orthonormal set of filters, followed by decimation (discarding the alternate samples). Data compression rates of 2:1, 4:1, 8:1, and so on are obtained at each successive scale. Four records each of normal sinus rhythm (NSR), supraventricular tachycardia (SVT), and ventricular tachycardia (VT) are analyzed. The performance of the MULTIWAVE algorithm is found to be superior to that of the TURNING POINT algorithm at all compression rates for all ECG records.