Effect of Ivabradine-Induced Heart Rate Reduction
Effect of Ivabradine-Induced Heart Rate Reduction
Numerous epidemiologic studies suggest that an elevated heart rate (HR) is associated with an increase in cardiovascular morbidity and mortality. This negative prognostic value of a higher HR appears to be independent of traditional cardiovascular risk factors. In addition, experimental and clinical evidence indicates that an increased HR contributes to the pathogenesis of atherosclerosis. Oxidative stress, expanded levels of low shear-stress periods and increased mechanical burden are discussed as underlying mechanisms. There are some clues that the HR modulates the endothelial function as well; however, results are controversial. Both positive as well as negative correlations of the HR with the FMD as parameter of endothelial-dependent vasodilation have been described.
Ivabradine (Iva), a selective inhibitor of If channels, reduces the resting and exercise HR without affecting cardiac contractility, blood pressure, intracardiac conduction, or ventricular repolarisation. It therefore offers the unique opportunity to assess effects of an exclusive HR reduction. Since it is presently unknown whether changes in the HR have an impact on the endothelial function in humans, the aim of our study was to investigate effects of a HR reduction in response to Iva on the endothelial function measured by the FMD of the brachial artery.
Background
Numerous epidemiologic studies suggest that an elevated heart rate (HR) is associated with an increase in cardiovascular morbidity and mortality. This negative prognostic value of a higher HR appears to be independent of traditional cardiovascular risk factors. In addition, experimental and clinical evidence indicates that an increased HR contributes to the pathogenesis of atherosclerosis. Oxidative stress, expanded levels of low shear-stress periods and increased mechanical burden are discussed as underlying mechanisms. There are some clues that the HR modulates the endothelial function as well; however, results are controversial. Both positive as well as negative correlations of the HR with the FMD as parameter of endothelial-dependent vasodilation have been described.
Ivabradine (Iva), a selective inhibitor of If channels, reduces the resting and exercise HR without affecting cardiac contractility, blood pressure, intracardiac conduction, or ventricular repolarisation. It therefore offers the unique opportunity to assess effects of an exclusive HR reduction. Since it is presently unknown whether changes in the HR have an impact on the endothelial function in humans, the aim of our study was to investigate effects of a HR reduction in response to Iva on the endothelial function measured by the FMD of the brachial artery.
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