Cardiac function in borderline hypothyroidism: a study by pulsed wave tissue Doppler imaging

Abstract

Objective: In subclinical hypothyroidism (SH), impaired diastolic function has been documented at rest and on effort, while systolic dysfunction has only been assessed on effort. Design: The aim of the present study was: (a) to further assess systolic function at rest in SH; and (b) to ascertain whether cardiac dysfunction could precede TSH increase in euthyroid patients with a high risk of developing SH. Methods: We studied 32 patients with classical Hashimoto's thyroiditis (22 with increased serum TSH (.3 mU/ml -group A), and 10 with normal serum TSH (,3 mU/ml -group B)); a third group (C), which included 13 healthy controls. All subjects underwent pulsed wave tissue Doppler imaging (PWTDI) to accurately quantify the global and regional left ventricular function. Results: When compared with group C, PWTDI indices showed that in both groups A and B there was a significant impairment of systolic ejection (P , 0.001 and P , 0.05, respectively), a delay in diastolic relaxation (P , 0.001 and P , 0.05, respectively) and a decrease in the compliance to the ventricular filling (P , 0.05). Several significant correlations were found between PWTDI parameters and serum-free T 3 and T 4 and TSH concentrations. Conclusion: PWTDI is a sensitive technique that allows detection of both diastolic and systolic abnormalities, not only in patients with SH, but also in euthyroid subjects with a high risk of developing thyroid failure. Futhermore, the significant correlations of several PWTDI indices with serum FT 3 and TSH concentrations strongly support the concept of a continuum spectrum of a slight thyroid failure in autoimmune thyroiditis extending to subjects with serum TSH still within the normal range.

Influence of the Subclinical Hypothyroidism on the Left Ventricular Systolic and Diastolic Function (pilot study)

“…In this study, the difference in EF of 3.4% was statistically significant. However, TDI analyses in other studies [13,22,23] showed disruption in LV systolic function in patients with ScH.…”

Subclinical Hypothyroidism Is Associated with Early Insulin Resistance in Kuwaiti Women

“…Among individuals with this condition, up to two-thirds have serum TSH levels between 5-10 mU/L and thyroid autoantibodies; almost half of them may progress to overt thyroid failure, the annual percent risk increasing with serum TSH level. When lasting more than 6-12 months, SH may be associated with an atherogenic lipid profile, a hypercoagulable state, a subtle cardiac defect with mainly diastolic dysfunction, impaired vascular function, and reduced submaximal exercise capacity [2]. The deviation from normality usually increases with serum TSH level ('dosage effect' phenomenon).…”

Tissue Doppler imaging – A sensible imaging option for the sensitive heart

“…There was no significant change in TD systolic (Sm) or diastolic (Em) velocity compared with normal controls. These changes were also positively correlated with TSH level [4]. Bioengineering studies have provided insights for the mechanism of change in TD timing intervals in SH patients.…”

“…With medical advances in the past decades new imaging techniques were emerged. Myocardial dysfunction in SH patients has been demonstrated by various imaging modalities including nuclear medicine [1], spectral pulse wave tissue Doppler (TD) echocardiography [4,5] and recently cardiac magnetic resonance imaging [6]. TD has an edge over the other two imaging modalities because of its convenience in use and good temporal resolution.…”