Abstract: Objective To access left ventricular global deformation abnormalities during low-dose dobutamine stress test (DSE)
by three-dimensional speckle-tracking echocardiography (3D-STE）in patients with non-ST-elevation acute coronary syndrome
(NSTE-ACS), and explore the diagnostic value of 3D-STE combined with DES for NSTE-ACS. Methods Forty-nine patients with
suspected NSTE-ACS underwent DSE and coronary angiography with an initial dobutamine dose of 5 μg·kg-1·min-1, which was
doubled at 3-min intervals to the peak dose of 20 μg·kg-1 ·min-1. The global longitudinal strain (GLS), global circumferential
strain (GCS), territory longitudinal strain (TLS), and territory circumferential strain (TCS) of the left ventricular subendocardial
myocardium were measured with 3D-STE at rest and at the peak-dose stage. Conventional echocardiography and 3D-STE
parameters and their changes during DSE were evaluated, and their diagnostic values were analyzed according to the
receiver-operating characteristic (ROC) curves. Results All the patients completed DSE uneventfully and 3D-STE showed a good
reproducibility of the results. Compared with patients with non-NSTE-ACS, NSTE-ACS patients showed obviously reduced
resting left ventricular global deformation function especially in terms of circumferential deformation (P<0.05); the ROC curves
for the parameters were similar between the two groups (P>0.05). During DSE, the global deformation differences between the
two groups further increased (P<0.01), and the diagnostic values of the peak-dose stage parameters were significantly greater
than those of the resting parameters. ROC curves analysis showed that TLS and TCS at peak-dose stage had the highest
diagnostic value for NSTE-ACS. Conclusion 3D-STE combined with low-dose DSE is a safe and effective noninvasive technique
for accessing and identifying NSTE-ACS, and DSE can significantly enhance the diagnostic value of 3D-STE.