Abstract

A real-time high-resolution ECG (HRECG) system was developed to study ventricular late potentials (VLP). In the denoising method, the SFP alignment technique was embedded in a pre-processing micro-controller to support the signal averaging process. This system is intended for screening subjects at cardiac risk in the out-of-hospital environment. It uses the fractal dimension of VLP (LPδ) as the diagnostic parameter. Performance of the SFP technique was tested by systematic 50Hz and EMG additive noise onto a noiseless ECG signal model of known spectrum. Spectral degradation due to the SFP based averaging, indicated a negligible beat alignment jitter SD under worst case of noise levels: ±2.6ms SD for 340µV (rms) of 50Hz noise, and ±1.3ms SD for 71µV (rms) of EMG noise type. In the LPδ verification method, the mean value of LPδ in five healthy volunteers was of 1.204 ±0.0526. A synthetic, coherent, and orthogonal LP signal injection at the body surface (with LPδ >1.36) indicated satisfactory LPδ parameter reproducibility