Cardiac autonomic function and global left ventricular performance in autoimmune eauthyroid chronic thyroiditis: is treatment necessary at the euthyroid stage?

Objective: Autoimmune chronic thyroiditis (ACT) is characterized by lymphocyte infiltration in the thyroid gland and the presence of antithyroid antibodies in serum. Medical treatment does not affect antibody levels and treatment decision is not definite yet for the euthyroid patients. We aimed to evaluate cardiac autonomic function and global left ventricular performance in autoimmune euthyroid chronic thyroiditis and determine the need for medical treatment.

Method: We studied 30 ACT patients and 25 healthy control subjects. Cardiac autonomic function is evaluated by heart rate recovery (HRR). Global left ventricular performance is evaluated by two-dimensional echocardiography and pulsed-wave tissue Doppler echocardiography.

Results: There was no difference between patients and controls with respect to clinical and biochemical parameters except hemoglobin (13.67 ± 1.25 g/dL, 14.51 ± 1.35 g/dL, p:0.047) and low density lipoprotein (120.71 ± 24.91 mg/dL, 100.55 ± 14.73 mg/dL, p: 0.003). Tei index was significantly higher in ACT group (0.521 ± 0.074, 0.434 ± 0.034, P < 0.0001). E'/A' was found to be significantly lower (1.234 ± 0.42, 1.750 ± 0.291, P < 0.0001) and E/E' was found to be higher than the controls (8.482 ± 0.449, 6.039 ± 0.209, P < 0.0001). HRR was significantly lower than the controls (20 ± 4 BPM, 30 ± 8 BPM, P < 0.0001).

Conclusion: Although left ventricular performance is found to be normal by conventional echocardiographic methods, it is found to be impaired when Tei index and tissue Doppler parameters are used. Cardiac autonomic function is also impaired in ACT patients. As a result of these cardiac changes, medical treatment may be considered earlier, even at the euthyroid stage.