Evaluation of cardiac functions in hypothyroidism and subclinical hypothyroidism before and after treatment

Abstract

Introduction: Hypothyroidism has been found to be associated with increased cardiovascular morbidity and mortality. Cardiac manifestations in hypothyroidism could be due to pericardial effusion (usually accumulates slowly), increased atherosclerosis risk , reduced heart rate and the contractile states of myocardium. It affects cardiac structures, function as well as cardiovascular hemodynamic.Aim: To evaluate cardiac functions in hypothyroidism and subclinical hypothyroidism before and after treatment.Materials and Methods: A prospective observational study including untreated 36 overt hypothyroid and 42 primary subclinical hypothyroid patients, age ranged 15-60 years. Included patients underwent clinical assessment, thyroid profile , 12 lead EGG, standard M-mode 2D echo and Doppler echocardiography before and 6 months after LT4 replacement therapy. Chi-square test was used to find statistical significance of change in mean values of various parameters obtained before and after treatment.Results: Majority of the study population (44.8%) were in the age group of 31-40 years with mean age being 38.5 ± 5.5 years, females accounted for 73.1% and males accounted for 26.9%.Among the overt hypothyroid group pretreatment heart rate was significantly lower (p<0.01) compared to post treatment, low voltage QRS complex was the common ECG finding and became normal post treatment,IVS and LVPW thickness decreased after treatment but it was not statistically, significant (p>0.05),diastolic dysfunction was noted in all patients and showed marked improvement after treatment (p<0.01).Among subclinical hypothyroidism patients abnormal LV diastolic filling (suggestive of impaired LV relaxation) was a common finding, EF an index of LV systolic function was comparable between pre and post treatment patients,diastolic functions were impaired in patients with stable subclinical hypothyroidism but reversible after 6 months of substitutive thyroxine therapy.Conclusion: Early detection and treatment of cardiac abnormalities in hypothyroidism prevents permanent structural abnormality of the heart.Doppler echocardiography technique is simple, reliable and reproducible method for assessment of cardiac functions in hypothyroidism