Spectral coherence between blood pressure and inter-beat intervals in hypertension
Danev, S.; Datzov, E.; Svetoslavov, S.; Mikhov, D.; Markova, P.; Girchev, R.
Central European Journal of Public Health 7(4): 185-188
1999
ISSN/ISBN: 1210-7778 PMID: 10659379 Document Number: 511402
Continuous registration of blood pressure (BP) was obtained in 31 normotensives and 76 hypertensives (divided into 3 stages of hypertension) by a method where the blood pressure in a human finger was measured non-invasively in a beat-by-beat fully calibrated manner. From this signal, the power density spectra of inter-beat intervals (IBI), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were derived. Total spectral power (TP) and low/high spectral frequency ratios of all spectra were calculated. Cross-correlation analysis between IBI, SBP and DBP spectra showed that the level of amplitude and phase spectral coherence (SC) was strongly dependent of the stage of hypertension. SC was calculated by means of appropriate mathematical algorithms. Multiple step regression analysis pointed out that the observed phenomenon is highly significant for both--the amplitude and the phase SC (p < 0.01).