Increased afterload increases SVR, which subsequently elevates the ascending aortic pressure. In case of significant AS, the effect of increased systemic central BP on intraventricular pressure might be minimal, and thus, TPG between LV and ascending aorta might be decreased because of relatively increased central aortic
pressure in comparison with intra-LV pressure. However, if the transmission of increased afterload into LV cavity per se were considerable, LV systolic wall stress would rise and lead to a decrease in LV systolic performance. In addition, increased LV afterload along with a decrease in SAC can attenuate LV CO,9) and finally result in a decrease Inhibitors,research,lifescience,medical in AV mean PG, AV Vmax, and AV peak PG. It may be possible that aortic root expansion also can increase CSALVOT during systole, Inhibitors,research,lifescience,medical and subsequently lead to commissural separation and finally stretch the free edge of the aortic valve leaflets. Although the effect of
aortic root expansion was previously reported in normal aortic valve,10),11) it appears to be unclear whether thickened and less mobile aortic valve and annulus can change their shape during LV afterload changes as normal aortic valve does. In this study, we found that LV EF, LV SV and CO did not change significantly with a maneuver leading to a rise in LV afterload. In order to achieve effective LV afterload increment http://www.selleckchem.com/products/incb28060.html without Inhibitors,research,lifescience,medical any influence of HR, we employed Pcom. Although we could did not directly measure intracardiac pressure, Pcom was considered very effective in modifying LV afterload, as demonstrated by a significant increase
in SVR. As shown in our representative cases in Fig. 2, TPG of AV, as represented by Inhibitors,research,lifescience,medical 2 parameters of AV Vmax and AV peak PG, was decreased under Pcom, suggesting the fact that an increase of aortic pressure was even greater than an increase of intra-LV pressure during systolic phase in the setting of LV afterload increment. On the Inhibitors,research,lifescience,medical other hand, EOAAV and Doppler velocity index did not change, indirectly highlighting that increased afterload did not modulate aortic root size or commissural opening of stenotic aortic valve in this special AS population. Fig. 2 Change of Doppler parameter after pneumatic compression. TVGpeak and TVPGmean were increased after pneumatic compression. On the other hand, Doppler index (TVILVOT/TVIAV) and calculated EOA did not change. Phosphatidylinositol diacylglycerol-lyase TVILVOT: time velocity integral of Doppler at … In this study, we used Pcom for experimental change in afterload. Pcom successfully increased LV afterload without a significant change in HR; however, Pcom possibly increases the venous return from lower extremities, which could explain, to some extent, increased E velocity, and slightly increased LV end-diastolic dimension. Increased preload can increase the stroke volume and possibly increase the AV Vmax of aortic valve.
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