title: The effect of heart rate on tricuspid annular velocities in cardiac surgical patients with atrial fibrillation.
abstract: OBJECTIVE
  Tricuspid annular isovolumic acceleration is a load-independent measure of contractility, but its relationship to heart rate is unknown in humans. The authors investigated the effect of heart rate on measurements of isovolumic acceleration and systolic wave velocities in postoperative cardiac surgical patients with atrial fibrillation.
  
  
  METHODS
  This was a prospective observational study.
  
  
  METHODS
  Single-university hospital setting.
  
  
  METHODS
  Postoperative cardiac surgical patients with atrial fibrillation.
  
  
  METHODS
  None.
  
  
  RESULTS
  Lateral tricuspid isovolumic acceleration and peak systolic wave velocity were measured using color-tissue Doppler. The corresponding heart rate was calculated from the preceding R-R interval. Regression analysis was used to assess the relationship between heart rate and tricuspid annular velocity. A heart rate threshold value was determined at which the tissue Doppler variables were significantly altered by heart rate. Seven hundred fifteen beats in 15 patients were analyzed. There was a positive linear correlation between isovolumic acceleration and heart rate and a negative polynomial correlation between the systolic wave and heart rate. A significant reduction in systolic wave velocity occurred at heart rates greater than 110 beats/min.
  
  
  CONCLUSIONS
  In this patient population, isovolumic acceleration significantly increased with increasing heart rate. Tachycardia-induced preload alterations and impaired force-frequency responses may have been responsible for the decrease in systolic wave velocities.
authors.affiliation: Department of Anesthesia and Critical Care, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Claude P
authors.initials: CP
authors.lastname: Tousignant
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Miller
authors.forename: André
authors.initials: A
authors.lastname: Denault
authors.forename: Li
authors.initials: L
authors.lastname: Zhu
authors.forename: Richard
authors.initials: R
authors.lastname: Bowry
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000209:etiology* / Q000503:physiopathology*; D013504:Cardiovascular Surgical Procedures / Q000009:adverse effects*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology; D011446:Prospective Studies; D014261:Tricuspid Valve / Q000502:physiology*