title: Relation of heart rate to left ventricular dimensions in normotensive, normal-weight children, adolescents and adults.
abstract: BACKGROUND
  The quantitative relation between body growth and changes in heart rate, and the relationship of heart rate to left ventricular (LV) dimensions, independent of the influence of body size, have been only marginally investigated. Accordingly, we designed this study to investigate the relation between heart rate, body size and LV dimensions in children, adolescents and adults over a broad age span.
  
  
  METHODS
  Eight hundred and nineteen normotensive, multi-racial, normal-weight individuals (444 males, 375 females, aged 1-85 years) with normal LV systolic function were studied at echocardiography in three centers, using previously reported methods. The resting heart rate was measured on the M-mode echo-tracing or right after the echocardiogram with the subject still in the supine position.
  
  
  RESULTS
  In children and adolescents (up to 17 years), the heart rate decreased with increasing body height (r = -0.51, p < 0.0001) and body weight (r = -0.42, p < 0.0001), in a similar manner in girls and boys. In adults, the heart rate was higher in women than in men, but it was not independently related to body size. The LV diastolic diameter was higher in males and decreased with increasing heart rate in children and adolescents (r = -0.45) as well as in adults (r = -0.25, both p < 0.0001). This relation was also independent of the effect of body size, sex and race. Similarly, the LV mass increased with decreasing heart rate in children and adolescents (r = -0.45), but the association was not confirmed after controlling for body size, sex and race. In adults, heart rate was inversely related to LV mass (r = -0.21, p < 0.0001), and this relation was also independent of body size, sex, race, age and blood pressure (p < 0.001). In women, the relation of heart rate to LV mass/height2.7 was less close than in men, due to the greater increase in LV mass with age.
  
  
  CONCLUSIONS
  The heart rate has an inverse association with the LV chamber diameter and with the LV mass in children-adolescents and in adults. This relation is largely, but not uniquely, mediated by body proportions, especially during body growth.
authors.affiliation: Division of Cardiology, Weill Medical College of Cornell University, New York, NY, USA. simogi@unina.it
authors.forename: G
authors.initials: G
authors.lastname: de Simone
authors.forename: R B
authors.initials: RB
authors.lastname: Devereux
authors.forename: T R
authors.initials: TR
authors.lastname: Kimball
authors.forename: M J
authors.initials: MJ
authors.lastname: Roman
authors.forename: V
authors.initials: V
authors.lastname: Palmieri
authors.forename: A
authors.initials: A
authors.lastname: Celentano
authors.forename: S R
authors.initials: SR
authors.lastname: Daniels
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001824:Body Constitution; D002648:Child; D002675:Child, Preschool; D006339:Heart Rate; D006352:Heart Ventricles / Q000033:anatomy & histology* / Q000254:growth & development; D006801:Humans; D007223:Infant; D008875:Middle Aged