title: Effects of early and late-onset treatment with carvedilol in an experimental model of aortic regurgitation.
abstract: BACKGROUND
  Beta-blockade is contraindicated in severe aortic regurgitation (AR) due to the fear of prolonging diastole and thus aggravate regurgitation. However, this has never been scientifically proven and positive effects of targeting the sympathetic system in AR has been demonstrated in several studies.
  
  
  METHODS
  Thirty-nine Sprague-Dawley rats with AR were randomized to ten weeks of medical treatment with carvedilol or no treatment. Treatment was initiated either early or late after AR induction. The effect of carvedilol was assessed by serial echocardiography and invasive hemodynamic measurements.
  
  
  RESULTS
  AR resulted in eccentric hypertrophy and left ventricular (LV) dysfunction. LV remodeling and function as measured by echocardiography was unaffected by treatment. LV dimensions were similar between treated and untreated groups and measures of LV performance (including strain and strain rate) were also unaltered. This result was confirmed by invasive measurements showing maximal and minimal pressure-time development, LV volumes, and LV pressures, to be unaltered by treatment. On the contrary, despite relative bradycardia carvedilol did not reflect any negative impact on the heart.
  
  
  CONCLUSIONS
  Carvedilol did not improve left ventricular remodeling or function in rats with surgically induced AR. Despite relative bradycardia, we did not find carvedilol to negatively impact the heart, either when treatment was initiated early or late in the course of disease.
authors: Johns Hopkins Medical Institutions, Division of Cardiology, 600 North Wolfe Street, Carnegie 568, Baltimore, MD 21287 USA ; Department of Cardiology, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark.
authors: Kristian
authors: K
authors: Eskesen
authors: Johns Hopkins Medical Institutions, Division of Cardiology, 600 North Wolfe Street, Carnegie 568, Baltimore, MD 21287 USA ; Department of Cardiology, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark.
authors: Niels Thue
authors: NT
authors: Olsen
authors: Johns Hopkins Medical Institutions, Division of Cardiology, 600 North Wolfe Street, Carnegie 568, Baltimore, MD 21287 USA.
authors: Veronica L
authors: VL
authors: Dimaano
authors: Department of Cardiology, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark.
authors: Thomas
authors: T
authors: Fritz-Hansen
authors: Department of Cardiology, Aalborg Hospital, University of Aalborg, Aalborg, Denmark.
authors: Peter
authors: P
authors: Sogaard
authors: Johns Hopkins Medical Institutions, Division of Cardiology, 600 North Wolfe Street, Carnegie 568, Baltimore, MD 21287 USA.
authors: Theodore P
authors: TP
authors: Abraham
keywords: Aortic regurgitation; Echocardiography; Experimental animal studies; Heart valvular disease; Invasive hemodynamic measurements