SPECTRAL-ANALYSIS OF 24-H BLOOD-PRESSURE RECORDINGS

Spectral analysis of blood pressure and heart rate signals allows over all blood pressure and heart rate variabilities to be split into their different frequency components. When used to analyze 24 h discontinuo us blood pressure recordings, the low sampling frequency that characte rizes these devices allows only the slow fluctuations in day and night blood pressure to be adequately described by the spectral approach. C onversely, spectral analysis of continuous blood pressure recordings p rovides information both on fast and slow changes in blood pressure an d heart rate. Because blood pressure and heart rate powers are charact erized by a 1/f distribution over the 24 h, slow fluctuations in blood pressure and heart rate contribute most importantly to 24 h variance, while faster components provide only a minor contribution. However, s pectral analysis of the latter has raised considerable interest due to the possible association of these components with cardiovascular regu latory mechanisms. It is now possible to perform 24 h dynamic spectral analysis of blood pressure and heart rate on continuous blood pressur e recordings obtained noninvasively by a finger pressure device.