STUDY OF LEFT VENTRICULAR FUNCTION BY SPECKLE TRACKING ECHOCARDIOGRAPHY AND CONVENTIONAL ECHOCARDIOGRAPHY IN PATIENTS WITH HYPERTHYROIDISM

BACKGROUND The main function of Thyroid hormones is to maintain a balance in cardiac function along with the regulation of metabolism. Any alterations in the thyroid hormone levels will further affect the normal functioning of the cardiac muscles. Initial raise in the hormones will result in increased contractility of the left ventricle resulting in the raise of cardiac output, whereas chronicity of the disease will cause reduction in normal behaviour of cardiac function, thereby causing increased risk of arrhythmias, reduction in global function of left ventricle, fibrosis and ultimately will result in heart failure. Cardiac dysfunction is one of the main causes of death in hyperthyroid cases, which is mainly due to remarkable changes in the haemodynamics resulting from abnormal muscle function of heart and diaphragm. Graves' disease was one of the commonest among the metabolic disorders to have its impact on cardiovascular system. MATERIALS AND METHODS This cross-sectional study was conducted in Narayana Hrudayalaya Hospital, Bangalore. All known cases of hyperthyroidism, irrespective of the duration of disease, irrespective of the gender and their geographical area of distribution, Males and Females >18 yrs. were all included in our study. The study was performed in the duration between April 2016 - April 2017. RESULTS A positive correlation was noted between left ventricular global longitudinal peak strain and left ventricular ejection fraction among 4% of the hyperthyroid cases, describing severe left ventricular systolic dysfunction. In our study, impaired myocardial relaxation was observed in 12% of the samples. Among them the LV systolic function assessed by conventional echocardiography showed normal LV ejection fraction, whereas AFI derived strain showed reduced global longitudinal peak strain values in 4% of the cases. Hence, we conclude that GLPS values are more sensitive than 2D EF to describe the early involvement of myocardial function impairment. CONCLUSION As per this study, there was significant correlation between TSH, T3, T4 thyroid hormones and 2D Speckle Tracking Echo in terms of Global Longitudinal peak strain of LV. Abnormal GLPS is a marker of early myocardial disease affecting the longitudinal myocardial fibres, which was found in the study. In terms of systolic and diastolic dysfunction, Tissue Doppler imaging was remarkably reduced in our study, which implies early changes in myocardial impairment.