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vol.22 issue1Cirugía cardíaca en octogenarios: Comparación de los resultados a corto y mediano plazo con la población menor a 80 años author indexsubject indexarticles search
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Revista Uruguaya de Cardiología

On-line version ISSN 1688-0420

Abstract

ZOCALO, YANINA et al. El endotelio mantiene elevada la capacidad de conducción arterial y reduce la poscarga dinámica ventricular de una manera frecuencia-dependiente. Rev.Urug.Cardiol. [online]. 2007, vol.22, n.1, pp.15-24. ISSN 1688-0420.

SUMMARY Introduction: The geometrical properties, the viscosity (V) and elasticity (E) of the arteries determine the arterial conduit (CF) and buffer (BF) functions, as well as the elastic (WE) and viscous (WV) work developed by the ventricle during the ejection (external dynamic afterload). It remains to be established the role of the endothelium in controlling V, CF, BF, WE and WV, and if the endothelium’s regulation of the dynamic afterload depends on the frequency. Objetive: To characterize the endothelial role in the regulation of V, CF, BF, WE and WV, and to analyze the endothelial control of the dynamic afterload during the increase in the frequency of stimulation. Methods: Ovine brachiocephalic arteries (n=9) were studied in a circulation mock during physiological haemodynamic conditions. Arterial flow, pressure and diameter were measured at 60, 80 and 100 cycles/minute. At each frequency E, V, CF, BF, WE y Wv, were calculated before and after the endothelium removal. Hystological studies verified the adequacy of the endotelial removal. Results: The endothelium allowed keeping E, V, WE and WV in low levels, and a high CF (p<0,05). The reduction in the afterload determinants was higher at higher levels of frequency (p<0,05). Conclusions: The endothelium regulates the arterial viscoelasticity, with a reduction in the dynamic afterload; at the time it allows keeping the CF at high levels, and does  not change the arterial auto-protection. The higher reduction in the afterload at high frequencies (increased oxigen demand), represents an additional beneficial effect in the ventricle function.

Keywords : ARTERY; BIOMECHANIC; ENDOTHELIUM; HEART RATE.

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