Introduction: Thyroid Hormones exert a direct cellular effect on almost all the tissues of the body including heart.Limited studies are available in the country to assess the various CVS parameters in hypothyroid patients and none have defined the impact of treatment on these parameters.

Aim and Objectives: To do an echocardiographic study of the cardiac changes in hypothyroidism and response to treatment

Methodology: 20 overt hypothyroid patients were selected , 12 males and 8 females and subdivided into 4 groups : untreated patients –A (14) , patients on L-thyroxin >=4 months –B(6) , control subjects matched by age and sex –C (10) , patient after treatment –D(6)-a subset of group A. Total T3 T4 was measured by RIA and TSH by IRMA.Echocardiography was done according to the standard protocols.

Results: With replacement therapy hypothyroid patients showed a decrease in wall thickness, decrease or disappearance of pericardial effusion and improvement in cardiac output. However no change in systolic function or size of various chambers were noted. Decreased cardiac output seen in untreated patients was mainly due to decreased heart rate.

Discussion: Present study showed relatively increased thickness of IVS and LVPW in untreated patients with marked difference in older patients consistent with other studies. There is a striking correlation between severity of disease and pericardial effusion. Following thyroid hormone replacement it was reported to resolve within few months.

Conclusion: All patients with unexplained PE should be screened for hypothyroidism. Echocardiography is useful in assessing the response to replacement therapy. With replacement therapy hypothyroid patients showed a decrease in wall thickness.