Cardiac Autonomic Function and Global Left Ventricular Performance in Autoimmune Eauthyroid Chronic Thyroiditis: Is Treatment Necessary at the Euthyroid Stage?

Impaired autonomic function and somatosensory disturbance in patients with treated autoimmune thyroiditis

Despite treatment with levothyroxine, hypothyroidism and autoimmune thyroiditis (AIT) may be associated with reduced quality of life (QoL), an enigmatic condition referred to as "syndrome T". Peripheral neuropathy, described in untreated thyroid disease, could be a contributing mechanism. We analysed autonomic and somatosensory function in 29 patients with AIT and treated hypothyroidism and 27 healthy volunteers. They underwent heart rate variability (HRV) analysis and quantitative sensory testing (n = 28), comprising 13 parameters of small and large nerve fibre function and pain thresholds. Autonomic cardiovascular function was assessed in rest, deep respiration and orthostasis. Additionally, biomarkers for autoimmunity and thyroid function were measured. Anxiety, depression and QoL were assessed using validated questionnaires. 36% of the patients showed at least one sign of somatosensory small or large fibre dysfunction. 57% presented with mild hyperalgesia to at least one stimulus. Several markers of autonomic function and some detection thresholds were related to the antibody titres. Anxiety, depression scores and QoL correlated to antibody titres and HRV measures. Autonomic and somatosensory dysfunction indicate that in treated hypothyroidism and AIT a subgroup of patients suffers from neuropathic symptoms leading to impaired QoL. Additionally, mild hyperalgesia as a possible sensitisation phenomenon should be considered a target for symptomatic treatment.

Evaluation of left atrial and ventricular myocardial functions by three-dimensional speckle tracking echocardiography in patients with euthyroid Hashimoto's thyroiditis

Hashimoto's Thyroiditis (HsT) is one of the most frequently occurring autoimmune diseases, characterized by lymphocytic infiltration, destruction and fibrosis of thyroid tissue and the presence of antibodies to thyroid peroxidase and thyroglobulin. The effects of euthyroid Hashimoto's thyroiditis (eHsT) on cardiovascular system are unclear. We aimed to identify if any deteriorations in LA and LV myocardial functions in patients with eHsT by 3D-STE in the current study. Fifty eight patients with eHsT and 60 age- and gender-matched controls were enrolled into the study. All participants underwent laboratory analyses which included thyroid hormones and thyroid autoantibody levels; and conventional 2D echocardiographic and 3D-STE analyses were performed. The mean age of the study patients was 34.5 ± 9 years, and 68.6% were female. Left ventricular global longitudinal strain (LV-GLS) was significantly depressed in the eHsT (+) group than in the control group (- 15.3 ± 3.6 vs. - 22.8 ± 3.8, p < 0.001). The LV-GLS was found to be disrupted linearly as thyroid autoantibodies increased (r = 0.684 for anti-TPO-ab and LV-GLS; r = 0.649 for anti-Tg-ab and LV-GLS). The present study demonstrated that 3D-STE is useful in the early detection of LV myocardial dysfunction in patients with eHsT. We found that eHsT had a negative effect on LV myocardial dynamics. According to these findings, these myocardial alterations that are present early in the disease process may be considered as a reason to start medical treatment earlier, even at the euthyroid stage to prevent LV myocardial impairment.

Subclinical Myocardial Dysfunction Demonstrated by Speckle Tracking Echocardiography in Children with Euthyroid Hashimoto’s Thyroiditis

Objective

Thyroid hormones have an important role in the regulation of the cardiovascular system. The aim of this study was to investigate the presence of subclinical myocardial dysfunction in children with euthyroid Hashimoto’s thyroiditis (eHT) without evident heart disease using tissue doppler imaging (TDI) and speckle tracking echocardiography (STE) methods.

Methods

TDI and STE were peformed in 50 children with eHT and in 35 healthy children. To assess myocardial velocities and time intervals, including peak systolic velocity (Sm), peak early diastolic velocity (Em), peak late diastolic velocity (Am), isovolumetric contraction time (IVCT), isovolumetric relaxation time (IVRT) and ejection time (ET), TDI was performed at the base of the interventricular septum (IVS) and in the left and right ventricles (LV and RV, respectively). Analysis of myocardial deformation by STE including strain (S) and strain rate (SR) was performed globally in two planes, longitudinal (L) and mid-circumferential (C) in LV [LV global longitudinal strain (LVGLS), LV global longitudinal strain rate (LVGLSR), LV global circumferential strain (LVGCS), LV global circumferential strain rate (LVGCSR)] and RV [(RV global longitudinal strain (RVGLS), RV global longitudinal strain rate (RVGLSR)].

Results

Among TDI parameters, ET at LV and IVS were significantly lower, IVRT and myocardial performance index at LV and IVS were significantly higher in the eHT group compared to controls (p=0.001). There were no significant differences in Sm, Em, Am and IVCT values between patients and controls. LVGLS, LVGLSR, LVGCS and LVGCSR values were significantly lower in patients than controls (p=0.01). There was a negative correlation between thyroid antibody levels and LV global longitudinal and circumferential strain and strain rate values (TPO-Ab and Tg-Ab between LVGLS, LVGLSR, LVGCS and LVGCSR; r=-411, p<0.001; r=-541, p<0.001; r=-430, p<.0.001; r=-502, r<0.01 and r=-397, p<0.001; r=-473, p<0.001; r=-519, p<0.001; r=-421, p<0.00, respectively).

Conclusion

The results show that myocardial function in children with eHT is impaired in the absence of any clinical symptoms and that conventional echocardiography is inadequate to determine these changes.

Echocardiographic Evaluation of Biventricular Function in Patients with Euthyroid Hashimoto's Thyroiditis

OBJECTIVE

The aim of this study was to evaluate the left (LV) and right (RV) ventricular function in euthyroid Hashimoto's thyroiditis (eHT) patients.

SUBJECTS AND METHODS

Forty-five patients diagnosed with eHT and 45 age- and gender-matched control subjects were enrolled in this study. Echocardiographic parameters reflecting RV and LV functions such as chamber dimensions, ejection fraction, fractional shortening, conventional and tissue Doppler-derived early and late filling velocities (E, A, E', A'), isovolumic relaxation (IVRT) and contraction (IVCT) times, ejection time (ET), deceleration time (DT), Tei index, pulmonary acceleration time (PAcT) and tricuspid annular plane systolic excursion (TAPSE) of patients with eHT were compared to those of control subjects using the paired-samples t test or Wilcoxon signed-rank test.

RESULTS

Regarding the LV function, compared to the controls patients with eHT had a higher LV-Tei index (0.6 ± 0.2 vs. 0.4 ± 0.1, p < 0.001), higher DT (p < 0.001) and IVRT (p < 0.001) values, and higher E/E' ratios (p = 0.04). In contrast, the peak E wave velocity (p = 0.02), E/A ratio (p = 0.01) and ET (p = 0.02) were significantly lower in the eHT group than amongst the controls. The RV, Tei index (0.40 ± 0.11 vs. 0.28 ± 0.07, p < 0.001), TAPSE (2.0 ± 0.3 vs. 2.2 ± 0.2 mm, p < 0.001), PAcT (124.3 ± 22.6 vs. 149.4 ± 18.3 ms, p < 0.001), A' (p = 0.007) and IVCT (p = 0.001) were significantly higher in patients with eHT than the controls. However, the tricuspid E/A ratio (p = 0.01), E' (p = 0.03) and E'/A' ratio (p = 0.001) were significantly lower in the eHT patients than the control group.

CONCLUSIONS

This study demonstrated that both RV and LV functions were impaired in patients with eHT.

Impact of overt and subclinical hypothyroidism on exercise tolerance: a systematic review

PURPOSE

This systematic review describes the state of the art of the impact of hypothyroidism on exercise tolerance and physical performance capacity in untreated and treated patients with hypothyroidism.

METHOD

A systematic computer-aided search was conducted using biomedical databases. Relevant studies in English, German, and Dutch, published from the earliest date of each database up to December 2012, were identified.

RESULTS

Out of 116 studies, a total of 38 studies with 1,379 patients fulfilled the inclusion criteria. These studies emphasize the multifactorial causes of exercise intolerance in untreated patients by the impact of limitations in different functional systems, with cardiovascular, cardiopulmonary, musculoskeletal, neuromuscular, and cellular metabolic systems acting in concert. Moreover, the studies affirm that exercise intolerance in patients is not always reversible during adequate hormone replacement therapy. As a consequence, despite a defined euthyroid status, there remains a significant group of treated patients with persistent complaints related to exercise intolerance who are suffering from limitations in daily and sport activities, as well as an impaired quality of life. An explanation for this phenomenon is lacking. Only 2 studies investigated the effects of a physical training program, and they showed inconsistent effects on the performance capacity in untreated patients with subclinical hypothyroidism.

CONCLUSIONS

A limited body of knowledge exists concerning exercise tolerance in treated patients with hypothyroidism, and there is an insufficient amount of quantitative studies on the effects of a physical training program. To enhance exercise and sports participation for this specific group, more research in this forgotten area is warranted.

Hashimoto's thyroiditis in patients with normal thyroid-stimulating hormone levels

Hashimoto's thyroiditis (HT) is one of the most common autoimmune endocrine disorders and often leads to hypothyroidism. It has been shown to substantially affect a patient's quality of life. Associated conditions and diseases were thought to be attributable to hypothyroidism. Yet, many patients still suffer from various symptoms even though all thyroid parameters are within the normal range. Independently of thyroid gland function, HT is associated with a wide range of organ-specific and non-organ-specific autoimmune disorders, as well as other diseases, including neuropsychological/psychiatric deficits, decreased left ventricular performance, disorders of the gut, fibromyalgia and reproductive health issues, among others. The underlying pathomechanisms remain unclear. Future treatment options might include thyroidectomy, selenium administration, prophylactic levothyroxine supplementation and dehydroepiandrosterone. However, further research is warranted to clarify the main pathophysiologic implications of thyroid autoimmunity and also to establish treatment options for euthyroid patients who suffer from HT-related symptoms and diseases.