Subclinical myocardial dysfunction in coronary slow flow phenomenon: identification by speckle tracking echocardiography.

OBJECTIVE: This study aimed to determine whether speckle tracking echocardiography (STE) could help detect subclinical myocardial dysfunction in patients with coronary slow flow phenomenon (CSFP).

METHODS: Sixty patients with CSFP confirmed by coronary angiography (CAG) and 51 controls with normal coronary flow were prospectively enrolled. Coronary angiographic data and conventional and speckle tracking echocardiographic parameters of the left ventricle (LV) and right ventricle (RV) were obtained for every subject.

RESULTS: Compared with controls, CSFP patients presented with higher BMI and TG levels, but lower HDL-C levels. Conventional echocardiographic parameters of biventricular systolic and diastolic function did not differ between the two groups (all P>0.05). The global longitudinal strain (GLS) of the LV and RV was significantly impaired in CSFP patients compared with that in controls (-19.03% vs. -21.42%, P<0.001 and -19.72% vs. -22.96%, P=0.001, respectively). The myocardial impairment pattern of CSFP patients was homogenous in the RV and heterogeneous in the LV, where only endo- and mid-myocardial layers were affected. LV-GLS and RV-GLS were found to be well correlated with mTFC and HDL-C in CSFP groups (r=0.463 vs. r=0.439; r=-0.569 vs. r=-0.552, all P<0.05). ROC curve analysis demonstrated that LV-GLS-endo had the highest AUC (0.867, P<0.001) for predicting subclinical myocardial impairment in CSFP patients.

CONCLUSIONS: Subclinical myocardial systolic dysfunction occurs in both ventricles, and GLS could be an effective method to detect early-stage myocardial impairment in patients with CSFP. This article is protected by copyright. All rights reserved.