title: Circadian heart rate and blood pressure variability considered for research and patient care.
abstract: OBJECTIVE
  To review mechanisms of circadian variations in heart rate variability (HRV) and blood pressure variability (BPV) and mortality and morbidity due to cardiovascular diseases (CVD).
  
  
  METHODS
  Results from 7-day/24-h HRV and BPV are interpreted by gender and age-specified reference values in the context of a Medline search.
  
  
  RESULTS
  Abnormal HRV and BPV measured around the clock for 7 days provides information on the risk of subsequent morbid events in subjects without obvious heart disease and without abnormality outside the conventional (in the sense of chronobiologically unquantified) physiological range. Meditation, beta-blockers, ACE inhibitors, n-3 fatty acids and estrogens may have a beneficial influence on HRV, but there is no definitive outcome-validated therapy. Low HRV has been associated with a risk of arrhythmias and arrhythmic death, unstable angina, myocardial infarction, progression of heart failure and atherosclerosis. BPV may be characterized by treatable circadian-hyper-amplitude-tension (CHAT), which can be transient '24-h CHAT' or '7-day-CHAT', MESOR-hypertension and/or an unusually-timed (odd) circadian acrophase (ecphasia), all associated with an increased risk of stroke, stroke death, myocardial infarction, and kidney disease.
  
  
  CONCLUSIONS
  Precise insight into the patho-physiology in time of HRV and BPV is needed with development of a consensus on best measures of HRV for clinical purposes and to determine when a 7-day record interpreted chronobiologically suffices and when it does not, for detection within as well as outside the conventional normal range, for diagnostic clinical practice and to direct therapy of risk greater than that associated with hypertension, smoking or any other risk factor.
authors.affiliation: Medical Hospital and Research Center, Civil Lines, Moradabad, India. icn@mickyonline.com
authors.forename: Ram B
authors.initials: RB
authors.lastname: Singh
authors.forename: Germaine
authors.initials: G
authors.lastname: Cornélissen
authors.forename: Andi
authors.initials: A
authors.lastname: Weydahl
authors.forename: Othild
authors.initials: O
authors.lastname: Schwartzkopff
authors.forename: George
authors.initials: G
authors.lastname: Katinas
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Otsuka
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Shoki
authors.initials: S
authors.lastname: Yano
authors.forename: Hideki
authors.initials: H
authors.lastname: Mori
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Ichimaru
authors.forename: Gen
authors.initials: G
authors.lastname: Mitsutake
authors.forename: Daniel
authors.initials: D
authors.lastname: Pella
authors.forename: Lu
authors.initials: L
authors.lastname: Fanghong
authors.forename: Ziyan
authors.initials: Z
authors.lastname: Zhao
authors.forename: Reema S
authors.initials: RS
authors.lastname: Rao
authors.forename: Anna
authors.initials: A
authors.lastname: Gvozdjakova
authors.forename: Franz
authors.initials: F
authors.lastname: Halberg
mesh_terms: D001794:Blood Pressure / Q000502:physiology*; D002318:Cardiovascular Diseases / Q000401:mortality / Q000503:physiopathology*; D002940:Circadian Rhythm / Q000502:physiology*; D016757:Death, Sudden, Cardiac / Q000517:prevention & control; D018450:Disease Progression; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D012307:Risk Factors