查看文章

Background: During low-dose dobutamine stress echocardiography in low-flow low-gradient aortic stenosis (LFLGAS), both the aortic stenosis severity and the presence of contractile reserve are conventionally assessed based on stroke volume flow reserve (SVFR)(stroke volume increase≥ 20%). However frequent exaggerated chronotropic response to dobutamine results in stroke volume drop, as opposed to transvalvular flow rate (FR)(stroke volume/ejection time) and left ventricular ejection fraction (LVEF) which may increase. We aimed to assess the value of FR≥ 200ml/s (normal FR) and LVEF change in the identification of true severe aortic stenosis (TSAS) and the assessment of contractile reserve respectively.

Methods: Accordingly 74 consecutive patients (mean age 78 years) with LFLGAS referred for low-dose dobutamine stress echocardiography for the determination of aortic stenosis severity and …