Left and right ventricular structure and function in subclinical hypothyroidism: the effects of one-year levothyroxine treatment.
BACKGROUND
The aim of this study was to investigate left ventricular (LV) and right ventricular (RV) structure, function, and mechanics in patients with subclinical hypothyroidism (SHT), and to evaluate the effect of a 1-year levothyroxine treatment.


METHODS
We compared 45 untreated women with subclinical hypothyroidism and 35 healthy control women matched by age. All the subjects underwent laboratory analyses, which included a thyroid hormone levels (free T3, free T4, and TSH) test, and a complete 2-dimensional echocardiographic study. All the SHT patients received levothyroxine therapy and were followed for a year after euthyroid state was achieved.


RESULTS
The LV mass index in the SHT participants before and after replacement therapy was significantly higher than in controls. In the SHT patients before the treatment, LV diastolic function and global function estimated by the Tei index were significantly impaired, whereas the LV systolic function was decreased. The results show that LV mechanics was significantly impaired in the SHT patients at baseline. Additionally, the SHT participants before levothyroxine substitution had increased RV wall thickness and significantly impaired RV diastolic and global function in comparison with the controls or the SHT subjects after the treatment. Furthermore, RV mechanics was also significantly deteriorated in the SHT patients before the treatment.


CONCLUSIONS
Subclinical hypothyroidism significantly affected LV and RV structure, systolic, diastolic and global function, and LV and RV mechanics. Levothyroxine replacement therapy significantly improved cardiac structure, function, and mechanics in the SHT patients.
Department of Endocrinology, University Clinical Hospital Center "Dr Dragisa Misovic", Belgrade, Serbia.
Sanja
S
Ilic
Marijana
M
Tadic
Branislava
B
Ivanovic
Zorica
Z
Caparevic
Bozo
B
Trbojevic
Vera
V
Celic
D004452:Echocardiography; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology / Q000187:drug effects*; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy*; D009929:Organ Size; D055771:Serbia; D018709:Statistics, Nonparametric; D013974:Thyroxine / Q000009:adverse effects* / Q000627:therapeutic use; D016276:Ventricular Function / Q000187:drug effects*
D013974:Thyroxine