1 Introduction
Echocardiography is the essential tool for assessing the severity of
aortic stenosis (AS).1-5 Peak transaortic valve jet
velocity (Vmax), mean transaortic valve pressure gradient (mPG), and
aortic valve area (AVA) are the main indexes of AS
severity.3,4 However, one or two indexes of them may
sometimes discord with each other, and require another solution. One of
the possible situations may be seen in case of depressed left
ventricular (LV) function. In case of AS with depressed LV function,
Vmax, mean PG, and stenotic AVA are underestimated because of reduced
stroke volume (SV) known as low-flow low-gradient (LFLG)
AS.6 In such cases, dobutamine stress echocardiography
is recommended for correct diagnosis of the severity of
AS.3,4,7
Ratio of acceleration time (AT) to ejection time (ET) of transaortic
flow, i.e. AT/ET, is reported as a reliable index of severity of
AS.8–12 AT/ET is positively correlated with Vmax,
mean PG, and negatively correlated with AVA or indexed AVA (AVAi). Also,
AT/ET is proposed as an alternative to detect prosthetic valve
malfunction caused by stenosis.13
To obtain the appropriate Vmax and mPG in patients with AS, approaching
by multiple acoustic windows are recommended by ASE
guideline.4 However, the acoustic window dependency on
the measurement of AT/ET have not been well studied yet, therefore, we
investigated the effect of different approach on AT/ET in patients with
AS.