Study of ECG changes in different thyrotoxic states and their correlation with thyroid hormone levels

Abstract

: Thyroid hormone has many recognized effects on the cardiovascular system that results in significant comorbidity and may also affect the quality of life of diseased person. : To assess the ECG changes in thyrotoxicosis with thyroid hormone level and secondary objectives are to compare different ECG pattern in thyrotoxicosis patients (Graves’ disease, Toxic multinodular goiter, Thyroid adenoma) with healthy individual taken as controls after exclusion of cardiovascular disorder, Hypertension.: Observational prospective case-controlled study include minimum 50 thyrotoxicosis patients and 50 control, done at Department of General Medicine MGM Medical college and MY Hospital Indore (MP). : In the present study peak incidence of thyrotoxicosis was observed in the age group of 35-50 years (50%), followed by in the age group of 20-34 years (36%). The female: male ratio in thyrotoxic group is 5.25:1. In this study Graves’ disease accounts most of the cases of thyrotoxic patients i.e., 84%. Sinus tachycardia was observed in 88.09% of Graves’ disease, 40% of toxic multinodular goiter, and 100% of thyroiditis. Atrial fibrillation was observed in 7.1% of Graves’ disease and 60 % of toxic multinodular goiter. Also, sinus tachycardia was observed in 63% of thyrotoxic patients who had free T3 level >2.4 ng/ml, in 100% of thyrotoxic patients who had free T3 level from 1.39-2.4 ng/ml, and in 81.8% of thyrotoxic patients who had free T3 level from 0.486-1.38 ng/ml. Atrial fibrillation was observed in 31.5% of thyrotoxic patients who had free T3 level >2.4 ng/ml. The patients having free T3 level from 1.39-2.4 ng/ml and 0.486-1.38 ng/ml does not show atrial fibrillation in ECG. The peak incidence of the thyrotoxicosis was found in the age group of 35-50 years (50%), younger patients age group of 20-50 years accounts 86% of total thyrotoxic patients and females were more affected than male. Graves’ disease accounts 84% cases of thyrotoxicosis. Thyrotoxic group and euthyroid group shows statistically significant ECG changes in terms of sinus tachycardia (<0.0001) and atrial fibrillation (0.0256). In the thyrotoxic group 82% of patient shows sinus tachycardia and 12% of patient shows atrial fibrillation. The association between sinus tachycardia, atrial fibrillation and total T3 level and free T3 level was found statistically significant (P=0.007).