1. Academic Validation
  2. Heart rate reduction induced by the if current inhibitor ivabradine improves diastolic function and attenuates cardiac tissue hypoxia

Heart rate reduction induced by the if current inhibitor ivabradine improves diastolic function and attenuates cardiac tissue hypoxia

  • J Cardiovasc Pharmacol. 2012 Mar;59(3):260-7. doi: 10.1097/FJC.0b013e31823e5e01.
Yuehua Fang 1 Manuelle Debunne Magali Vercauteren Ebba Brakenhielm Vincent Richard Francoise Lallemand Jean-Paul Henry Paul Mulder Christian Thuillez
Affiliations

Affiliation

  • 1 INSERM U644, Institut Hospitalier Recherche BioMedicale Normandie, IFRMP n°23, UFR de Médecine et de Pharmacie, Rouen, France.
Abstract

Aims: Enhanced heart rate (HR) is a compensatory mechanism in chronic heart failure (CHF), preserving cardiac output, but at the cost of increased left ventricular (LV) oxygen consumption and impaired diastolic function. The HR reduction (HRR) induced by the If current inhibitor ivabradine prevents LV systolic dysfunction in CHF, but whether HRR improves LV diastolic function is unknown.

Methods: LV diastolic function and remodeling were assessed in rats with CHF after coronary ligation after long-term (90 days, starting 7 days after ligation) and delayed short-term (4 days, starting 93 days after ligation) ivabradine treatment (10 mg·kg·d).

Results: Long- and short-term HRR reduced LV end-diastolic pressure, LV relaxation, and LV end-diastolic pressure-volume relation. Simultaneously, LV hypoxia-inducible factor-1α expression was reduced. Long-term and, to a more marked extent, short-term HRR increased endothelial cell proliferation, associated after long-term HRR with the prevention of CHF-related LV capillary rarefaction. Long-term and, to a lesser extent, short-term HRR increased endothelial nitric oxide synthase expression, associated after long-term HRR with improved nitric oxide-dependent coronary vasodilatation.

Conclusions: Long-term HRR induced by ivabradine improves diastolic LV function probably involving attenuated hypoxia, reduced remodeling, and/or preserved nitric oxide bioavailability, resulting from processes triggered early after HRR initiation: angiogenesis and/or preservation of endothelial nitric oxide synthase expression.

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