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


METHODS
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.


CONCLUSIONS
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.
Zoncu
Sandra
S
Department of Cardiovascular Sciences, University of Cagliari, Sardinia, Italy.
Pigliaru
Francesca
F
Putzu
Claudia
C
Pisano
Lorella
L
Vargiu
Sara
S
Deidda
Martino
M
Mariotti
Stefano
S
Mercuro
Giuseppe
G
D000328:Adult; D003971:Diastole; D018619:Echocardiography, Doppler, Pulsed; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D007037:Hypothyroidism / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D013599:Systole; D013961:Thyroid Gland / Q000503:physiopathology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine