To analyze the changes of myocardial perfusion and the characteristics of left ventricular (LV) rotation and LV twist (LVTW) in patients with coronary slow flow (CSF), and to assess the relationship between them by using dobutamine stress real-time myocardial contrast echocardiography (RTMCE) and speckle tracking echocardiography (STE).

A total of 54 patients who underwent coronary angiography for angina were enrolled at the Affiliated Hospital of Hangzhou Normal University, of whom 33 with CSF were included as a CSF group and 21 with normal coronary angiography findings were included as a control group. After conventional echocardiography, LV end diastolic volume (LVEDV) and LV ejection fraction (LVEF) were measured by the biplane Simpson method. And basal and apical rotation of the LV (R_basal and R_apical) were calculated via Qlab10.4 analysis software offline, the time to basal and apical peak rotation of the LV (TPR_basal and TPR_apical) were calculated through graphics semi-automatically, and LVTW and rotation deformation delay (RDD) were also calculated. RTMCE was performed from the apical 4-, 3-, and 2-chamber views at baseline and after dobutamine stress echocardiography, and parameters including myocardial blood volume (A), myocardial blood velocity (β), myocardial blood flow (MBF), and myocardial flow reserve (MFR) were obtained. The correlation between R_apical/LVTW and MBF/MFR was analyzed.

LVEDV and LVEF had no significant difference between the two groups. Compared with the control group, R_apical, LVTW, and RDD significantly decreased and TPR_apical significantly increased in CSF patients (U=2.707, t=-2.379, t=-4.988, and t=2.422, respectively; P<0.05). At baseline, the value of β in the CSF group was significantly lower than that in the control group (t=-2.218, P<0.05). After dobutamine stress test, patients with CSF showed significantly decreased β, MBF, and MFR (t=-3.791, -2.612, and -2.585, respectively; P<0.05) compared with the control group. Pearson correlation analysis revealed that R_apical and LVTW were correlated with MBF both at rest (r=0.502 and 0.462, respectively; P<0.05) and after dobutamine stress test (r=0.436 and 0.368, respectively; P<0.05).

Both R_apical and LVTW are impaired in CSF patients, and coronary microcirculation disorder could be an important contributor to the decrease of left ventricular rotation and twist motion.