| Objective To assess the characteristics of left ventricular rotation and twist in patients with silent myocardial ischemia by using three-dimensional speckle tracking echocardiography (3D-STE), and to explore the application of this technology in evaluating left ventricular systolic function.Methods In our hospital,66patients with silent myocardial ischemia who established by selective coronary artery angiography were included in this study from September2011to December2012. According to Gensini score, these patients were further divided into3subgroups:mild lesion group (n=16), moderate lesion group (n=26) and severe lesion group (n=24). Other30patients suspected of having silent myocardial ischemia but received a negative result in selective coronary angiography as the control group. The left ventricular three-dimensional entire volume dynamic images were obtained and stored for off-line analysis by using3DT software. Then parameters were collected, of which including left ventricular peak rotation in basal plane (peak basal rotation, Prot-B) and aplical plane (peak aplical rotation, Prot-A), left ventricular peak twist in basal plane (peak basal twist, Ptw-B) and aplical plane (peak aplical twist, Ptw-A), left ventricular peak apical rotation(LVrot) and twist (LVtw).The left ventricular ejection fraction (LVEF) was also calculated by using Simpson dual plane. The wall motion score index (WMSI) was assessed as well. Finally, the above-mentioned indicators in silent myocardial ischemia group compare to that in control group.Results (1)No significant difference in LVEDd, LVESd, WMSI or LVMI was detected between the mild lesion group and control group (all P>0.05); however, LVEDd, LVESd, WMSI and LVMI in moderate lesion group and severe lesion group was higher than that in mild lesion group or control group (P<0.05), but LVEF exhibited an opposite phenomenon (P<0.05); moreover, a greater increase of LVEDd, LVESd, WMSI, LVMI and a significant decrease of LVEF were observed in severe lesion group compared to moderate lesion group (all P<0.05).(2) No statistically significant difference in apical heart horizontal rotation angle peak, peak left ventricular rotation angle and the twist angle was detected between the mild lesion group and control group (P>0.05); nevertheless, these indicators in the moderate lesion group were significantly decreased when compared with the mild group or the control group (P<0.05); further decrease was observed in the severe lesion group.(3)LVEF, Prot-A, Prot-B, Lvrot and LVtw in silent myocardial ischemia group were negatively correlated with coronary angiography Gensini score, while WMSI, LVEDd, LVESd, LVMI were positively related to Gensini score. Furthermore, a significant relation of LVEF, WMSI, Prot-A, Prot-B, Lvrot and LVtw to Gensini score was also observed (all P<0.01).(4) Prot-A, Prot-B, LVrot and LVtw assessed by3D-STE can be superior to the traditional ultrasound measurement data LVEF and WMSI for accurate diagnosing silent myocardial ischemia and evaluating left ventricular systolic function of these patients (P<0.05or P<0.01). Among the above-mentioned3D-STE parameters, Prot-A and LVtw exhibited a higher diagnostic sensitivity and specificity, respectvely.Conclusion The three-dimensional speckle tracking echocardiography can determine the different coronary lesions in patients with silent myocardial ischemia by assessing left ventricular rotation and twisting motion variation and can sensitively reflect the changes of in left ventricular systolic function. The investigation can also indirectly identify which main coronary branch may be involved in the pathological changes and the severity of silent myocardial ischemia. Therefore it may provide an important reference value for the treatment and prognosis of silent myocardial ischemia. |
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