Objectives To explore myocardial perfusion of patients with coronary slow flow (CSF) using myocardial contrast echocardiography.
Methods Myocardial contrast echocardiography was performed in coronary artery angiography diagnosed CSF patients (n = 20) and control patients (n = 20). The images at baseline and after low dose dobutamine stress test were analysed by automatic tracking software and the maximal amplitude score A, the mean ascending slope of the curve β and the product of A·β were measured. The reserve of A·β was also calculated. Electrocardiogram at rest and at each stage of dobutamine stress test was obtained simultaneously.
Results At baseline, the A (6.85 ± 2.99 dB vs. 7.01 ± 3.49 dB), β (0.59 ± 0.33 s-1 vs. 0.61 ± 0.38 s-1) and A·β (3.48 ± 1.46 dB/s vs. 3.31 ± 0.96 dB/s) values were similar between CSF group and control group (all P > 0.05). After dobutamine stress test, both β and A·β were significantly increased in two groups. The β (0.89 ± 0.42 s-1 vs. 1.31 ± 0.54 s-1, P < 0.01) and A·β (5.82 ± 2.69 dB/s vs. 8.07 ± 2.76 dB/s, P < 0.05) in CSF group were significantly lower than in control group. Electrocardiogram of all the subjects was normal at rest, but the electrocardiogram positive rate was significantly higher in CSF group than in control group after dobutamine stress test (12% vs. 2%, 60% vs. 10%, P < 0.01).
Conclusions Dobutamine stress test could induce myocardial perfusion abnormalities in patients with coronary slow flow phenomenon.