Spectral characteristics of ventricular response to atrial fibrillation.
To investigate the spectral characteristics of the fluctuation in ventricular response during atrial fibrillation (AF), R-R interval time series obtained from ambulatory electrocardiograms were analyzed in 45 patients with chronic AF and in 30 age-matched healthy subjects with normal sinus rhythm (SR). Although the 24-h R-R interval spectrum during SR showed a 1/f noise-like downsloping linear pattern when plotted as log power against log frequency, the spectrum during AF showed an angular shape with a breakpoint at a frequency of 0.005 +/- 0.002 Hz, by which the spectrum was separated into long-term and short-term components with different spectral characteristics. The short-term component showed a white noise-like flat spectrum with a spectral exponent (absolute value of the regression slope) of 0.05 +/- 0.08 and an intercept at 10(-2) Hz of 4.9 +/- 0.3 log(ms2/Hz). The long-term component had a 1/f noise-like spectrum with a spectral exponent of 1.26 +/- 0.40 and an intercept at 10(-4) Hz of 7.0 +/- 0.3 log(ms2/Hz), which did not differ significantly from those for the spectrum during SR in the same frequency range [spectral exponent, 1.36 +/- 0.06; intercept at 10(-4) Hz, 7.1 +/- 0.3 log(ms2/Hz)]. The R-R intervals during AF may be a sequence of uncorrelated values over the short term (within several minutes). Over the longer term, however, the R-R interval fluctuation shows the long-range negative correlation suggestive of underlying regulatory processes, and spectral characteristics indistinguishable from those for SR suggest that the long-term fluctuations during AF and SR may originate from similar dynamics of the cardiovascular regulatory systems.
Hayano
J
J
Third Department of Internal Medicine, Nagoya City University Medical School, Japan.
Yamasaki
F
F
Sakata
S
S
Okada
A
A
Mukai
S
S
Fujinami
T
T
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000503:physiopathology*; D002940:Circadian Rhythm; D004232:Diuretics; D015716:Electrocardiography, Ambulatory; D005260:Female; D017709:Fractals; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D016276:Ventricular Function
D004232:Diuretics