Abstract

Introduction: Hypothyroidism is the most common form of thyroid disorder throughout the world. It is a clinical state which results from deficient production of thyroid hormonedue to structural and/functional abnormalities. Diastolic dysfunction is defined as left ventricular diastolic dysfunction indicating a functional abnormality of diastolic relaxation, elasticity or distensibility of the left ventricle, regardless of whether the left ventricle ejection fraction is normal or abnormal and whether the patient is symptomatic or not.

Aims and Objectives: The objective of the study will be to examine the effect of thyroid hormone replacement (L-thyroxine) on left ventricular diastolic dysfunction in patients with overt hypothyroidism¹⁹.

• What percentage of hypothyroid patients have left ventricle diastolic dysfunction.
• Whether this diastolic dysfunction could be reversed by thyroxine treatment.
• To see if any correlation exists between serum TSH and Doppler echocardiography findings regarding diastolic dysfunction of left ventricle.

Materials: Among 120 Hypothyroidism patients 50 patients were found to have Echo-doppler criteria of left ventricular diastolic dysfunction. These 50 patients were finally selected for the study.

Patient with clinical features suggestive of hypothyroidism will be selected from OPD & IPD of katihar medical college &hospital. Patient will be assessed clinically & will be subjected to Thyroid Function Test, Blood Sugar, Lipid Profile, Chest X-Ray, and Echocardiography i.e 2D M Mode and Doppler technique will be used.

50 Patients with raised TSH (>5ml/L10)⁶⁴and Echocardiographic finding of left ventricular diastolic dysfunction will be selected for the study.

One hundred and twenty patients were selected from our Medicine and Endocrinology outdoor and indoor medical wards of Katihae Medical College And Hospital. After selection they were evaluated by Doppler echocardiography study. Among 120 patients, 50 patients were found to have Echo-doppler criteria of left ventricular diastolic dysfunction. These 50 patients were finally selected for the study.

Left ventricular diastolic dysfunction was considered when; (Echodoppler criteria)

E_max (early diastolic filling velocity of mitral valve) was decreased compared to A_max (Late diastolic filling velocity of mitral valve) i.e, E_max<A_max and their ratio E/Amax is less⁶³ than one (E/A =1.7+/-0.6,normal range)

Mitral E wave decleration time (peak of E wave to end of E wave, i.e, DT) and Isovolumic relaxation time(IVRT) with higher than normal values also reflected diastolic dysfunction.(DT=184+/-24msec, IVRT=74+/-26msec,normal range)⁶⁵.

Diastolic Inter Ventricular septal thickness (d-IVST) , Diastolic left ventricular posterior wall thickness (d-LVPET), Left ventricular end diastolic diameter (LVEDD) will be evaluated.

50 patient with age sex matched controls will be taken for comparative study to see wheather Left Ventricular Diastolic dysfunction is more common in hypothyroidism.

These 50 patients will be treated with Levothyroxine. After 3 month, Thyroid profile and Echocardiography will be repeated to see if Left ventricular diastolic dysfunction improves with it.

Inclusion Criteria: Aged between 15 to 70 years; With positive clinical history of increased TSH Level.

Exclusion Criteria: valvular abnormalities, Congenital heart disease, Arrhythmias, Hypertrophic cardiomyopathy, Pericardial disease, Ischemic heart disease, LVH, Systemic illness like DM, hypertension.

Duration of study: Dec2016 – May2018.

Results: In this study among 120 hypothyroidism patients 50 patients having diastolic dysfunction.  Improvement in the left ventricular diastolic function following L-thyroxine replacement therapy was observed in all the patients during follow-up. After 3 months of treatment along with an increase in E_max( increased from 60.14 + 8.12 cm/sec to 76.43+5.26 cm/sec) there was a significant decrease in A_max i.e. late diastolic filling velocity of mitral valve (from 79.40 + 11.21 cm/sec to 63.76+10.12 cm/sec), leading to an increase in E/A _max ratio from 0.7498 + 0.084 to 1.21+0.10. This signified a reversal of the diastolic dysfunction of the left ventricle. There was also a decrease in isovolumic relaxation time from 95.50+5.92 to 83.09 +6.04msec (IVRT) and deceleration time of mitral E wave  (DT) from 237.26+14.33msec to 213.8 + 10.68msec – indicating an overall improvement in the diastolic function of the left ventricle. We also found a significant decrease in left ventricular end diastolic diameter (LVEDD), inter ventricular septal thickness (IVST) & left ventricular .posterior wall thickness (LVPWT) and IVST/LVPWT ratio after 3 months of therapy- suggesting structural changes of left ventricle. But there is slight change in only EF%. seen.

Conclusion: The subsequent improvement in overall diastolic function of left ventricle in patients with L-Thyroxine therapy was possibily related to continued to biochemical and structural changes in myocardium. However a long term follow up using 2D Echocardiography required.