title: Heart rate-dependent left ventricular diastolic function in patients with and without heart failure.
abstract: BACKGROUND
  Chronic heart rate (HR) reduction in the treatment of heart failure (HF) with systolic dysfunction is beneficial, but the immediate mechanical advantages or disadvantages of altering HR are incompletely understood. We examined the effects of increasing HR on early and late diastole in humans with and without HF.
  
  
  RESULTS
  We studied force-interval relationships of the left ventricle (LV) in 11 HF patients and 14 control subjects. HR was controlled by right atrial pacing, and LV pressure was recorded by a micromanometer-tipped catheter. The time constant of isovolumic relaxation (tau) was calculated, and simultaneous sonographic images were analyzed for LV volumes. The end-diastolic pressure-volume relationship (EDPVR) was analyzed with the use of a single-beat method. Tau was shortened in response to increasing HR in both groups; the slope of this relationship was steeper in HF than in control subjects. The predicted volume at a theoretic pressure of 0 mm Hg (V30) increased at higher HRs compared with baseline, shifting the predicted EDPVR compliance curve to the right in HF patients but not in control subjects.
  
  
  CONCLUSIONS
  In HF, changes in HR affect early relaxation and diastolic compliance to a greater extent than in control subjects. Our study reinforces current recommendations for HR-lowering drug treatment in HF.
authors.affiliation: Division of Cardiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada; Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Sam
authors.initials: S
authors.lastname: Esfandiari
authors.affiliation: Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada.
authors.forename: Felipe
authors.initials: F
authors.lastname: Fuchs
authors.affiliation: Division of Cardiology, Hospital de Clinicas de Porto Alegre, Porto Alegre, Brazil.
authors.forename: Rodrigo V
authors.initials: RV
authors.lastname: Wainstein
authors.affiliation: Division of Cardiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Anjala
authors.initials: A
authors.lastname: Chelvanathan
authors.affiliation: Division of Cardiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Peter
authors.initials: P
authors.lastname: Mitoff
authors.affiliation: Division of Cardiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Zion
authors.initials: Z
authors.lastname: Sasson
authors.affiliation: Division of Cardiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada. Electronic address: smak@mtsinai.on.ca.
authors.forename: Susanna
authors.initials: S
authors.lastname: Mak
mesh_terms: D000328:Adult; D000368:Aged; D006328:Cardiac Catheterization / Q000379:methods; D002304:Cardiac Pacing, Artificial / Q000379:methods; D003971:Diastole / Q000502:physiology; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000503:physiopathology* / Q000628:therapy; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: Heart failure; diastole; heart rate; left ventricle