Assessment of the left ventricular systolic function in cardiac syndrome X using speckle tracking echocardiography

Impact of Coronary Microvascular Dysfunction on Myocardial Strain in Patients with Heart Failure and Preserved Ejection Fraction

Background

This research aimed to evaluate the role of coronary microvascular dysfunction in alteration of left ventricular (LV) myocardial deformation.

Materials and Methods

This observational study involved 50 patients with LV ejection fraction (LVEF) >50% and coronary microvascular dysfunction (diagnosed by coronary angiography). TIMI frame count (TFC) was calculated for each patient. They were classified into 2 groups: 30 patients with heart failure and preserved ejection fraction (HFpEF) (cases group) and 20 patients without HF (control group). Speckle tracking echocardiography was used to evaluate LV deformation.

Results

The mean age of the studied patients was 58.8 ± 8 years. The frequency of diabetes mellitus, hypertension, and dyslipidemia were significantly higher in cases than controls. Cases had significant higher BMI (30 ± 4.48 vs. 27.3 ± 3.94 kg/m2, P=0.029). The total TFC in cases was 97.1 ± 22.9 and in controls was 79 ± 18.5, and this difference was statistically significant (P=0.005). Significantly decreased LV global strain was observed in HFpEF cases than in controls (-17.6 ± 2.14 % versus -19.5 ± 1.98%, P < 0.001). In cases with a higher TFC, the LV global strain decrease was more pronounced. There was a significant correlation between the LV global strain and total TFC (r=-0.470 and P=0.009).

Conclusion

Patients with HFpEF exhibited higher total TFC reflecting more affected coronary microvasculature. Those patients had reduced LV global strain. Coronary microvascular dysfunction probably leads to alteration of myocardial performance.

Evaluation of left ventricular systolic function in patients with different types of ischemic heart disease by two-dimensional speckle tracking imaging

Background

The purpose of this study was to evaluate left ventricular systolic function in patients with different types of ischemic heart disease using two-dimensional speckle tracking imaging (2D-STI).

Methods

We retrospectively studied patients who were admitted to Peking University Third Hospital from January 2011 to December 2017 due to chest tightness and chest pain. Two hundred forty-two patients were divided into control group, CMD group and obstructive CAD group. The main coronary artery stenosis was confirmed by coronary angiography or coronary computed tomography and coronary flow reserve (CFR) in patients was measured by transthoracic Doppler echocardiography. Left ventricular strain and strain rate (SR) measured by 2D-STI. Cardiac structure and function were measured by conventional echocardiography.

Results

Conventional echocardiography showed that there was no significant difference in cardiac structure and function among the three groups (P > 0.05). Moreover, the longitudinal strain (LS) of each ventricular wall in CMD group was notably lower than that in control group (P < 0.01). In addition, global longitudinal SR and longitudinal SR in CMD group and obstructive CAD group were obviously lower than those in control group (P < 0.01). GLS, endocardial LS and epicardial LS were negatively correlated with CFR (P < 0.01).

Conclusions

Early left ventricular systolic dysfunction was found in patients with CMD and patients with obstructive CAD, with similar degree. CFR is an independent influencing factor of GLS. GLS and stratified LS have certain diagnostic value for CMD.

Coronary microvascular dysfunction in diabetes mellitus

The significance, mechanisms and consequences of coronary microvascular dysfunction associated with diabetes mellitus are topics into which we have insufficient insight at this time. It is widely recognized that endothelial dysfunction that is caused by diabetes in various vascular beds contributes to a wide range of complications and exerts unfavorable effects on microcirculatory regulation. The coronary microcirculation is precisely regulated through a number of interconnected physiological processes with the purpose of matching local blood flow to myocardial metabolic demands. Dysregulation of this network might contribute to varying degrees of pathological consequences. This review discusses the most important findings regarding coronary microvascular dysfunction in diabetes from pre-clinical and clinical perspectives.