title: The influence of circadian variations on echocardiographic parameters in healthy people.
abstract: BACKGROUND
  Our aim was to investigate whether diastolic functions, myocardial velocities and pulmonary vein flow show diurnal variation within a 24-hour day.
  
  
  RESULTS
  Fourty-four healthy subjects with no history of cardiovascular or systemic diseases (32 males, 12 females; mean age 34.7 ± 8.7 years, mean BMI: 25.5 ± 3.5 kg/m(2)) were enrolled in this study. None of the subjects had a history, symptoms or signs of cardiovascular or systemic diseases or were taking drugs of any kind. All underwent echocardiographic examination at 7 a.m., 1 p.m., 7 p.m., and 1 a.m. M-mode systolic, diastolic velocities and pulmonary vein flow measurements were obtained. There were no differences in systolic and diastolic blood pressures and heart rate. The left atrial diameter was greater at 1 p.m. (3.80 ± 0.44; P = 0.031). The isovolumic contraction time (ICT) was found to be the shortest (41 ± 12 msn; P = 0.050), and ejection time (ET) the longest (290 ± 31 msn; P = 0.017) at the 1 am measurements. The mitral myocardial performance index (MPI) was lowest during the 1 a.m. measurements (0.42 ± 0.11; P = 0.001). The systolic myocardial velocities (Sm) obtained from the septum and inferior region were significantly higher at 1 p.m. and lower at 7 a.m. (9.17 ± 1.79, 10.25 ± 2.29; 8.11 ± 1.06, 8.63 ± 1.49; P < 0.05). The late diastolic velocities obtained from the lateral, inferior and anterior regions were higher at 1 p.m. and 7 p.m.
  
  
  CONCLUSIONS
  The left ventricular diameter and ejection fraction did not exhibit circadian variations. However, our data indicate that some parameters reflecting diastolic function, systolic myocardial velocities and MPI, as well as left atrial diameter change at different times of the day, independent of blood pressure and heart rate.
authors.affiliation: Department of Cardiology, Faculty of Medicine, Zonguldak Karaelmas University, Zonguldak, Turkey. turgutkarabag@yahoo.com
authors.forename: Turgut
authors.initials: T
authors.lastname: Karabag
authors.forename: Mustafa
authors.initials: M
authors.lastname: Aydin
authors.forename: Sait Mesut
authors.initials: SM
authors.lastname: Dogan
authors.forename: Muhammet Rasit
authors.initials: MR
authors.lastname: Sayin
authors.forename: Mehmet Ali
authors.initials: MA
authors.lastname: Cetiner
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D004452:Echocardiography; D005260:Female; D006321:Heart / Q000502:physiology*; D006801:Humans; D008297:Male; D011667:Pulmonary Veins / Q000000981:diagnostic imaging* / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013318:Stroke Volume / Q000502:physiology*; D017725:Ventricular Pressure / Q000502:physiology*