Hardware design for the computation of heart rate variability

The decrease in heart rate variability is an indication of abnormal heart function. Proposed here is a hardware design of a standalone system that calculates and evaluates heart rate variability, distinguishing healthy from unhealthy subjects. Previous approaches are mostly based on the fast Fourier transform and the power spectral analysis. Described is an alternative approach thatfollows a recently proposed idea: the analysis of heart rate signals with the use of wavelets. The proposed system follows simple gated architecture and is composed offour main units: a processing unit that prepares the input signal for analysis, a unit that manages control signals, the wavelet computation unit and the wavelet coefficient evaluation unit. The hardware design is cost-effective, simple and easy to implement. Experimental results proved that this system is efficient and produces a clean and accurate separation between the healthy and unhealthy groups of patients for the first nine scales of wavelet analysis.