Microcomputerized on-line evaluation of heart rate variability power spectra in humans

The heart rate variability power spectra is computed using an on-line microcomputer system. In normal subjects (n = 10), standing and post-exercise states demonstrated statistically significant increases (p less than 0.05) in the peak power at 0.1 Hz. During exercise, the peak power at 0.1 Hz was reduced significantly (p less than 0.05). In patients with myocardial infarction, either the peak at 0.1 Hz or the peak associated with breathing frequency was augmented. Our system is mobile and is useful especially when on-line heart rate variability power spectra are required in experimental or clinical situations.