Heart rate reduction with ivabradine prevents the global phenotype of left ventricular remodeling

Am J Physiol Heart Circ Physiol. 2011 Jan;300(1):H366-73. doi: 10.1152/ajpheart.01117.2009. Epub 2010 Oct 15.

Abstract

The aim of this study was to investigate the effect of chronic heart rate (HR) reduction with the hyperpolarization-activated current inhibitor ivabradine on the global phenotype of left ventricular (LV) remodeling in a ligated rat model. Seven days after coronary artery ligation, Wistar rats received ivabradine (10 mg · kg(-1) · day(-1) administered in drinking water) [myocardial infarction + ivabradine (MI+IVA), n = 22] or vehicle only (drinking water) (MI, n = 20) for 90 days. A sham group (n = 20) was included for model validation. MI+IVA rats had 12% lower HR (P < 0.01), improved LV volumes, 15% higher LV ejection fraction (LVEF, P < 0.01) than MI rats, and 33% reductions in both plasma atrial natriuretic peptide (ANP, P = 0.052) and cardiac hydroxyproline. Using patch-clamp, action potential duration was reduced and transient outward current density increased (P < 0.05). Cardiac energy metabolism was also improved (+33% creatine phosphate, P < 0.001; +15% ATP; and +9% energy charge, P < 0.05). Significant correlations were found between HR and parameters of cardiac metabolism, ANP, and LVEF (all P < 0.05). The HR-reducing properties of ivabradine prevent changes in the global phenotype of LV remodeling in the rat, optimize energy consumption, and avoid electrophysiological and structural remodeling.

MeSH terms

  • Action Potentials / drug effects
  • Action Potentials / physiology
  • Animals
  • Benzazepines / pharmacology*
  • Electrocardiography
  • Energy Metabolism / drug effects
  • Energy Metabolism / physiology
  • Heart / drug effects*
  • Heart / physiopathology
  • Heart Rate / drug effects*
  • Heart Rate / physiology
  • Ivabradine
  • Male
  • Myocardial Infarction / metabolism
  • Myocardial Infarction / physiopathology
  • Myocardium / metabolism
  • Rats
  • Rats, Wistar
  • Ventricular Function, Left / drug effects*
  • Ventricular Function, Left / physiology
  • Ventricular Remodeling / drug effects*
  • Ventricular Remodeling / physiology

Substances

  • Benzazepines
  • Ivabradine