Influence of clenbuterol treatment during six weeks of chronic right ventricular pressure overload as studied with pressure-volume analysis

J Thorac Cardiovasc Surg. 2001 Oct;122(4):767-74. doi: 10.1067/mtc.2001.114354.

Abstract

Objectives: Chronic pressure overload cardiac hypertrophy produces ventricular dysfunction. There is evidence that clenbuterol, a beta(2)-adrenoceptor agonist, produces cardiac hypertrophy with preserved function in rodents. We sought to determine the cardiac hypertrophic effects of clenbuterol on the thin-walled ventricles of large animals undergoing chronic pressure overload by means of pulmonary artery banding.

Methods: Right ventricular pressure-volume loops were obtained in open-chest sheep before and after 6-1/2 weeks of pulmonary artery banding by using micromanometer conductance catheters. Animals were randomly assigned to treatment with either saline solution (n = 7) or clenbuterol (n = 8). Treatment was started immediately after pulmonary artery banding.

Results: Acute pulmonary artery banding increased the right ventricular systolic pressure equally in both groups (saline group, 23.9 +/- 3.3 to 48.1 +/- 9.7 mm Hg; clenbuterol group, 24.3 +/- 2.8 to 48.6 +/- 10.7 mm Hg [mean +/- standard deviation]). Six weeks of treatment produced no significant differences in the body weight, heart weight, heart/body weight ratio, right ventricular wall thickness, heart rate, and stroke volume between the groups. However, the slope of the end-systolic pressure-volume relation and the slope of the first derivative of the right ventricular developed pressure/end-diastolic volume relation were significantly increased when compared with baseline values in clenbuterol-treated animals but not in saline-treated animals.

Conclusion: Clenbuterol treatment during pulmonary artery banding improves systolic function of the chronically pressure-overloaded right ventricle. This has important implications for the use of pharmacologic agents in modulating cardiac adaptation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic beta-Agonists / pharmacology*
  • Animals
  • Clenbuterol / pharmacology*
  • Heart Ventricles / growth & development
  • Hemodynamics / drug effects
  • Random Allocation
  • Sheep
  • Systole
  • Time Factors
  • Ventricular Pressure / drug effects*
  • Ventricular Pressure / physiology

Substances

  • Adrenergic beta-Agonists
  • Clenbuterol