Left Ventricular Twist Mechanics Are Impaired in Patients with Coronary Slow Flow

Coronary slow flow (CSF) is a rare condition described as the delayed angiographic passage of a contrast agent in the absence of stenosis in epicardial coronary arteries. Left ventricular (LV) systolic and diastolic dysfunctions have been described in the presence of CSF. However, the effect of CSF on LV twist functions has not been assessed. We aimed to evaluate the effects of CSF on LV twist mechanics using speckle tracking echocardiography (STE).

Twenty CSF patients (24-60 years) were enrolled according to the exclusion criteria. Twenty subjects with similar demographic characteristics and normal coronary arteries were the controls. Participants were evaluated with conventional echocardiography and STE.

The general characteristics of the two groups were similar. LV twist, LV torsion, and apical rotation were impaired in the CSF group (P = 0.015, P = 0.012, and P < 0.001, respectively). Time to peak twist (TPT) and time to peak untwisting (TPU) were prolonged in CSF patients (P < 0.001 and P < 0.001, respectively). In the CSF group, rotation-deformation delay was shortened (P < 0.001) and global longitudinal strain (GLS) was lower (P < 0.001). The thrombolysis in myocardial infarction (TIMI) frame count was negatively correlated with LV twist, LV torsion and apical rotation (P = 0.002, r = -0.624; P = 0.002, r = -0.624; and P = 0.002, r = -0.632, respectively).

We demonstrated that LV twist mechanics are impaired in CSF patients. Worse LV twist parameters were associated with greater TIMI frame count.