Left ventricular dysfunction in patients with subclinical hypothyroidism and its reversibility after hormone therapy

To ascertain the presence of LV dysfunction in patients of subclinical hypothyroidism and its reversibility after hormone therapy. METHODS AND METERIAL: Thirty two patients with subclinical hypothyroidism (SH) were included in the study, along with thirty two age and sex matched individuals serving as controls. The patients with SH had normal serum T3 and T4 with an elevated TSH value. All patients and the controls were subjected to detailed echocardiographic examination for assessment of LV systolic and diastolic function before and one year after hormone (thyroxine) therapy.

The systolic function of LV was normal in patients with SH. There was significant diastolic dysfunction in the SH patients as compared with controls. There was prolongation of deceleration above time (169 +/- 6.1 msec. vs. 148.1 +/- 5.4 msec in controls, p < 0.05), isovolumic relaxation time (89.1 +/- 7.3 msec vs. 79.4 +/- 5.9 msec., p<0.05), increased A wave (0.63 +/- 0.6 m/sec. vs. 0.54 +/- 0.05 m/sec) and reduced E/A ratio (0.7 +/- 0.09 vs. 1.4 +/- 0.3, p < 0.05). Echocardiography at the end of one year of hormone therapy revealed considerable improvement in diastolic function of the LV. There was significant improvement in DT (from 169 +/- 6.1 msec. to 151 +/- 5.2 msec, p < 0.05), IVRT (from 89.1 +/- 7.3 msec. to 80.2 +/- 6.5 msec, p < 0.05) and increased E/A ratio (from 0.7 +/- 0.09 to 1.3 +/- 0.1, p < 0.05).

Hypothyroidism, even in subclinical stage, can cause diastolic dysfunction of the LV. These abnormalities in diastolic function can be reversed by thyroxine therapy.