title: Deceleration time of left ventricular outflow tract flow as a simple surrogate marker for central haemodynamics at rest and as well as during exercise.
abstract: BACKGROUND
  The shape and duration of left ventricular outflow tract (LVOT) flow has not been applied to assess the central haemodynamics, although LVOT flow is confronted with afterload of arterial system during systole. The aim of this study was to evaluate whether the LVOT flow parameters are related with central systolic blood pressure (BP) and arterial compliance at rest and as well as during exercise.
  
  
  METHODS
  We studied 258 subjects (175 females, age 61 ± 11 years) with normal left ventricular (LV) systolic function who underwent supine bicycle stress echocardiography and arterial tonometry simultaneously at rest and at peak exercise. Deceleration time (DT) of LVOT flow and RR interval were measured and deceleration time corrected for heart rate (DTc) was calculated. Peripheral and central haemodynamic parameters including systolic and diastolic BP, and augmentation index at a heart rate of 75 (AIx@75) were assessed using radial artery tonometry. Carotid femoral pulse wave velocity (PWV) was measured.
  
  
  RESULTS
  Deceleration time corrected for heart rate was independently associated with central systolic BP and AIx@75 at rest (P < 0.001 and 0.006). Similarly, it also showed significant independent correlations with central systolic BP and AIx@75 during peak exercise (P = 0.006 and P = 0.021). In addition, DTc which measured both at rest and at peak exercise demonstrated significant positive correlations with PWV, suggesting association of prolonged DTc with arterial stiffening (P = 0.023 and P = 0.005).
  
  
  CONCLUSIONS
  Prolongation of LVOT flow DTc represents raised central systolic BP and increased arterial stiffness not only at rest but also during exercise. Therefore, central aortic pressures and arterial stiffness influence the DT of LVOT flow at rest as well as during exercise in individuals with normal LV systolic function.
authors.forename: In-Jeong
authors.initials: IJ
authors.lastname: Cho
authors.forename: Chi Young
authors.initials: CY
authors.lastname: Shim
authors.forename: Sun-Ha
authors.initials: SH
authors.lastname: Moon
authors.forename: Hyun-Jin
authors.initials: HJ
authors.lastname: Lee
authors.forename: Geu-Ru
authors.initials: GR
authors.lastname: Hong
authors.forename: Namsik
authors.initials: N
authors.lastname: Chung
authors.forename: Jong-Won
authors.initials: JW
authors.lastname: Ha
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000032:analysis; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000502:physiology; D015331:Cohort Studies; D003654:Deceleration; D025401:Echocardiography, Stress / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D063177:Pulse Wave Analysis / Q000379:methods*; D012189:Retrospective Studies; D013318:Stroke Volume / Q000502:physiology*; D013997:Time Factors; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D015415:Biomarkers
keywords: Doppler echocardiography; arterial stiffness; left ventricular outflow tract