|Lobnig BM et al.|
Repeatability of Heart Rate Variability Measured via Spectral Analysis in Healthy Subjects
Journal of Clinical and Basic Cardiology 2003; 6 (1-4): 29-33
Keywords: Autonomes Nervensystem, Herzfrequenz, Kardiologie, Spektralanalyse, Variabilitšt, Autonomic nervous system, cardiology, heart rate, spectral analysis, variability
Objective was to characterize reproducibility of heart rate variability measurements via spectral analysis during repeated measurements in young healthy subjects. Up to now, reproducibility of heart rate variability has been characterized in a variety of disease states but not extensively in healthy subjects. In a cross-sectional design, healthy volunteers from the hospital staff of a university medical school were recruited. The measurement error of short-term coarse-graining spectral analysis was calculated by 2 methods. Repeated measurements during controlled breathing were performed in seven healthy subjects three times a day during a single session. Such sessions were repeated on a median of 4 days for each subject. Total spectral power in the high and low frequency domain was measured and log transformed. Repeatability was calculated from intra-individual standard deviation as described by Bland and Altman and was also expressed as the intra-class correlation coefficient (ICCC). A total number of 73 observations was obtained for each frequency domain. The intra-class correlation coefficient ranged from 0.658 to 0.807 in the supine and from 0.326 to 0.567 in the standing position. Repeatability ranged from 1.366 to 1.733 ln (ms2) in the supine position and from 1.857 to 2.205 ln (ms2) in the standing position. As a conclusion, a poor reproducibility is obtained in the standing position. In supine position, a medium reproducibility is obtained in the low frequency domain, but a good reproducibility in the high frequency domain. Measurements on different days do not contribute to the variance of spectral power measurements.