Study of association between subclinical hypothyroidism on diastolic function of the heart

Abstract

Background: Thyroid dysfunction is known problem in Indian population, vary from
hypothyroidism to hyperthyroidism. Subclinical hypothyroidism is defined biochemically as
a normal serum free thyroxine (T4) concentration in the presence of an elevated serum
thyroid-stimulating hormone (TSH) concentration. Our study aimed to study the association
between subclinical hypothyroidism on diastolic function of the heart. Material and
Methods: Present study was single-center, case control study, conducted patients more than
18 years age, had elevated TSH level higher than the upper limit range 4mU/L but below
10mU/l and normal levels of T3 and T4 without any clinical features of hypothyroidism.
Present study involved 31 Subclinical hypothyroid and 31 normal individuals with normal
thyroid profile. Results: There was a statistically significant difference found between cases
and controls with respect to Total Cholesterol. There was a statistically significant difference
found between cases and controls with respect to Peak E-early mitral flow rate, Peak A-late
mitral flow rate, E/A ratio, E/E’-early mitral flow velocity/mitral valve tissue velocity. There
was no statistically significant difference found between cases and controls with respect to
DT-deceleration time. Among those who have sub clinical hypothyroidism 45.2% have
abnormal peak E value when compared to 3.2% among controls and this was found to be
statistically significant. Similirly 25% of the cases were found to have abnormal peak and
3.2% of the cases were found to be statistically significant. E/A ratio was significant in cases
when compared to controls with 29% being abnormal in cases and 3.2% in the controls. DT
and E/E' was not significant. Conclusion: Subclinical hypothyroidism is significantly
associated with symptomatic with NYHA GRADE 2 breathlessness as well as left ventricular
diastolic Dysfunction. Evaluation by 2D echocardiography in patients with subclinical
hypothyroidism helps for early detection, treatment & follow-up