title: Reproducibility and relation to mean heart rate of heart rate variability in normal subjects and in patients with congestive heart failure secondary to coronary artery disease.
abstract: Before heart rate (HR) variability can be used for predictive purposes in the clinical setting, day-to-day variation and reproducibility need to be defined as do relations to mean HR. HR variability and mean HR were therefore determined in 2 successive 24-hour ambulatory electrocardiograms obtained from 33 normal subjects (age 34 +/- 7 years, group I), and 22 patients with coronary disease and stable congestive heart failure (CHF) (age 59 +/- 7 years, group II). Three measures were used: (1) SDANN (standard deviation of all mean 5-minute normal sinus RR intervals in successive 5-minute recording periods over 24 hours); (2) SD (the mean of the standard deviation of all normal sinus RR intervals in successive 5-minute recording periods over 24 hours); and (3) CV (coefficient of variation of the SD measure), a new measure that compensates for HR effects. Group mean HR was higher and HR variability lower in group II than in group I (80 +/- 10 vs 74 +/- 9 beats/min, p less than 0.04). Mean group values for HR and HR variability showed good correlations between days 1 and 2 (mean RR, r = 0.89, 0.97; SDANN, r = 0.87, 0.87; SD, r = 0.93, 0.97; CV, r = 0.95, 0.97 in groups I and II, respectively). In contrast, considerable individual day-to-day variation occurred (group I, 0 to 46%; group II, 0 to 51%). Low HR variability values were more consistent than high values. SDANN and SD correlated moderately with HR in both groups (r = 0.50 to 0.64). The CV measure minimizes HR effects on HR variability.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medicine, Northwestern University Medical School, Chicago, Illinois 60611.
authors.forename: D
authors.initials: D
authors.lastname: Van Hoogenhuyze
authors.forename: N
authors.initials: N
authors.lastname: Weinstein
authors.forename: G J
authors.initials: GJ
authors.lastname: Martin
authors.forename: J S
authors.initials: JS
authors.lastname: Weiss
authors.forename: J W
authors.initials: JW
authors.lastname: Schaad
authors.forename: X N
authors.initials: XN
authors.lastname: Sahyouni
authors.forename: D
authors.initials: D
authors.lastname: Fintel
authors.forename: W J
authors.initials: WJ
authors.lastname: Remme
authors.forename: D H
authors.initials: DH
authors.lastname: Singer
mesh_terms: D000328:Adult; D000368:Aged; D003327:Coronary Disease / Q000150:complications*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006333:Heart Failure / Q000209:etiology / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications; D015203:Reproducibility of Results; D012737:Sex Factors; D013997:Time Factors