Real-time system for high-resolution ECG diagnosis based on 3D late potential fractal dimension estimation

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 (LP_δ) 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 LP_δ verification method, the mean value of LP_δ in five healthy volunteers was of 1.204 ±0.0526. A synthetic, coherent, and orthogonal LP signal injection at the body surface (with LP_δ >;1.36) indicated satisfactory LP_δ parameter reproducibility.