Metabolic syndrome, strain, and reduced myocardial function: multi-ethnic study of atherosclerosis

Abstract

Background: Subclinical cardiovascular disease is prevalent in patients with Metabolic Syndrome (MetSyn). Left ventricular (LV) circumferential strain (εCC) and longitudinal strain (εLL), assessed by Speckle Tracking Echocardiography (STE), are indices of systolic function: shortening is indicated by negative strain, and thus, the more negative the strain, the better the LV systolic function. They have been used to demonstrate subclinical ventricular dysfunction in several clinical disorders.

Objective: We hypothesized that MetSyn is associated with impaired myocardial function, as assessed by STE.

Methods: We analyzed Multi-Ethnic Study of Atherosclerosis (MESA) participants who underwent STE and were evaluated for all MetSyn components.

Results: Among the 133 participants included [women: 63%; age: 65 ± 9 years (mean ± SD)], the prevalence of MetSyn was 31% (41/133). Individuals with MetSyn had lower εCC and lower εLL than those without MetSyn (-16.3% ± 3.5% vs. -18.4% ± 3.7%, p < 0.01; and -12.1% ± 2.5% vs. -13.9% ± 2.3%, p < 0.01, respectively). The LV ejection fraction (LVEF) was similar in both groups (p = 0.09). In multivariate analysis, MetSyn was associated with less circumferential myocardial shortening as indicated by less negative εCC (B = 2.1%, 95%CI:0.6 3.5, p < 0.01) even after adjusting for age, ethnicity, LV mass, and LVEF). Likewise, presence of MetSyn (B = 1.3%, 95%CI:0.3 2.2, p < 0.01) and LV mass (B = 0.02%, 95% CI: 0.01-0.03, p = 0.02) were significantly associated with less longitudinal myocardial shortening as indicated by less negative εLL after adjustment for ethnicity, LVEF, and creatinine.

Conclusion: Left ventricular εCC and εLL, markers of subclinical cardiovascular disease, are impaired in asymptomatic individuals with MetSyn and no history of myocardial infarction, heart failure, and/or LVEF < 50%.

Figure 1

Representative LV ε_CC curve from a participant without MetSyn. Different colors depict different myocardial segments. The white strain curve represents the global circumferential peak strain. ES: end-systole; ε_CC: circumferential strain; LV: left ventricle.

Figure 2

Representative LV ε_LL curve from a participant with MetSyn. Different colors depict different myocardial segments. The white strain curve represents the global longitudinal peak strain. ES: end-systole; εLL: longitudinal strain; LV: left ventricle; LA: Left atrium; RV: Right ventricle; RA: Right atrium; MV: Mitral valve