Extracting the heart rate variability from an electrocardiogram sampled at a very low frequency

Our study focuses on a new method of estimating the heart rate variability (HRV) which does not need the use of R-wave detection from the electrocardiogram (ECG). Contrary to this detection method which requires a sampling frequency higher than 100 Hz, the one proposed here could calculate the HRV from an ECG signal sampled around 5 Hz with a mean error of 0.03 beats/sup -1/. The method also worked efficiently to extract the HRV from an ECG measured from a subject in an exercise condition. The overall error was smaller as we low-pass filtered the heart rate variability.