title: Is blunted heart rate decrease at night associated with prevalent organ damage in essential hypertension?
abstract: OBJECTIVE
  The association between a blunted decrease in day–night heart rate and subclinical organ damage has not been investigated earlier in human hypertension. Therefore, we assessed such an association in a cohort of 658 untreated essential hypertensive patients.
  
  
  METHODS
  All patients underwent procedures including cardiac and carotid ultrasonography, 24-h urine collection for microalbuminuria, ambulatory blood pressure monitoring with simultaneous assessment of heart rate over two 24-h periods within 4 weeks. Nondipping heart rate was defined as a mean heart rate reduction at night lower than 10% compared with daytime values.
  
  
  RESULTS
  A reproducible nocturnal dipping (heart rate decrease >10% in both the ambulatory blood pressure monitoring periods) and nondipping profile was found in 513 (78%) and 76 patients (12%), respectively; 69 hypertensive patients (10%) had a variable dipping profile. The three groups did not differ with regard to age, sex, body size, metabolic variables, office and ambulatory blood pressures, left ventricular mass, carotid intima-media thickness, carotid plaque and microalbuminuria. In a univariate analysis, the decrease in nocturnal heart rate did not correlate with any parameter of subclinical organ damage.
  
  
  CONCLUSIONS
  Our findings from a cross-sectional study do not support the view that a flattened heart rate circadian rhythm is related to a prevalent organ damage in essential hypertension and that this altered pattern is a marker for subclinical cardiovascular disease. The prognostic significance of this finding should be defined by prospective studies.
authors.affiliation: Department of Clinical Medicine and Prevention, University of Milano-Bicocca, Milan, Italy. cesare.cuspidi@unimib.it
authors.forename: Cesare
authors.initials: C
authors.lastname: Cuspidi
authors.forename: Stefano
authors.initials: S
authors.lastname: Meani
authors.forename: Francesca
authors.initials: F
authors.lastname: Negri
authors.forename: Cristiana
authors.initials: C
authors.lastname: Valerio
authors.forename: Carla
authors.initials: C
authors.lastname: Sala
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Mancia
mesh_terms: D000328:Adult; D018660:Blood Pressure Monitoring, Ambulatory; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000378:metabolism; D003430:Cross-Sectional Studies; D005260:Female; D006339:Heart Rate; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000378:metabolism; D006801:Humans; D006973:Hypertension / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000652:urine; D008297:Male; D008875:Middle Aged; D012890:Sleep; D014463:Ultrasonography