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

The aim of this study was to evaluate left ventricular (LV) systolic strain by speckle tracking echocardiography (STE) and real-time three-dimensional echocardiography (3-DE) for the early detection of myocardial dysfunction in patients with cardiac syndrome X (CSX).

We compared 34 patients with CSX (18 females, mean age 47.9±10.0 years) with 41 healthy persons as a control group (23 females, mean age 50.6±9.9 years). Inclusion criteria for CSX were typical angina, a positive exercise ECG stress test, and angiographically documented normal coronary arteries. Exclusion criteria for both groups were hypertension, valvular heart disease, cardiomyopathies, inflammatory diseases, myocarditis, vasculitis, arthropathies, Tietze's syndrome, gastrointestinal diseases, aortic diseases, hormone replacement therapy, arrhythmias, liver diseases, and alcohol use. All subjects underwent two-dimensional STE and 3-DE to assess resting LV function. STE measures were taken from the basal septum, mid-septum, apical septum, apex, apicolateral, mid-lateral, basal lateral, anteroseptal, anterior, anterolateral, inferolateral, inferior, and inferoseptal walls. Student's t-test, Mann-Whitney U test, and chi-square test were used to statistically analyze data.

LV echo ejection fraction (EF) and systolic wave peak velocity were similar for both groups. Regional mean longitudinal strain (-17.7±2.5% vs. -19.8±1.8%; p<0.0001) was significantly lower in patients with CSX than in healthy control patients. However, regional mean circumferential strain values (-22.0±1.6% vs. -22.2±2.3%; p=0.78) did not differ significantly between the two groups.

Significant impairment of LV longitudinal myocardial systolic function was detected with STE in patients with CSX, although normal 3-D EF and tissue Doppler imaging systolic parameters were observed. Arteriosclerosis of small coronary arteries and microvascular dysfunction may affect myocardial longitudinal strain.