ECG changes in patients with primary hyperthyroidism

Abstract

IntroductionThyroid hormones plays key role in regulating cardiovascular system. Its imbalance leads to various electrophysiological changes in cardiovascular system. This study was done to determine the frequency of electrocardiographic (ECG) changes in patients with primary hyperthyroidism.MethodsIt was a descriptive cross-sectional study conducted in the Department of Medicine, Medical Unit III, Ward-7, Jinnah Postgraduate Medical Centre, Karachi, from October 2013 to April 2014. A total of 103 patients newly diagnosed with primary hyperthyroidism were included in this study. Venous blood samples were collected for T3, T3, TSH analyzed by radioimmunoassay. ECG was performed. Outcome variables were the ECG changes i.e. sinus tachycardia and atrial fibrillation.ResultsThe average age of the patients was 30.09±5.57 years (95%CI: 29 to 31.18). Out of 103 cases, 19 (18.45%) were male and 84 (81.55%) were female. Sinus tachycardia was observed in 60.19% (62/103) patients whereas atrial fibrillation was found in 11.65 (12/103) of cases.ConclusionIn this study frequency of electrocardiographic changes in term of sinus tachycardia was high. This report has emphasized the importance of thyrotoxicosis as a cause of cardiac morbidity and mortality in patients with thyrotoxicosis. These cardiac complications are readily reversible if timely optimal treatment is offered.

A meta-analysis of ECG abnormalities (arrhythmias) in different types of heart failure

“…Besides supraventricular arrhythmias, the other most commonly studied cardiac arrhythmias are ventricular arrhythmias, which arise from the AV junction or within the AV node itself and include ventricular tachycardia (VT) and ventricular fibrillation (VF). The present meta-analysis found ventricular arrhythmias in 272 out of 973 HF patients in six studies [27][28][29]31,35,44] translating into an event rate of 32.0% (95% CI: 12.2% to 61.3%; Figure 3). Among ventricular arrhythmias, VT was the most prevalent, reported in 9,061 out of 114,035 HF patients in four large HF registries [16,19,21,26] translating into an event rate of 5.6% (95% CI: 3.9% to 7.9%; Figure 4).…”

“…The 22 studies included countries in America (the U.S and Canada), Europe (the U.K., Netherlands, Denmark, and the Czech Republic), Asia (Japan, Pakistan, India), and Africa (sub-Saharan Africa, Nigeria, and Ghana). Together, the11 registries and 22 HF studies only evaluated a few types of HF, which included thyrotoxic HF [27][28][29][30][31], HFrEF [18,23,25,[32][33][34][36][37][38][39][40], ischemic [34,41], HFpEF [25,35], HFmEF [25], hypertensive [18,23,26,47,48], right HF [18], and systolic HF [42][43][44][45][46].…”

“…Other studies categorized HF type based on the causative agent rather than functional changes but, in effect, relied on LVEF values to confirm HF diagnosis. These studies categorized HF into hypertensive, ischemic and thyrotoxic [27][28][29][30][31]34,41,47,48]. Thus, based on the classification adopted, the different types of HF may share common clinical characteristics.…”

“…Further analysis examined the prevalence of AF in different HF types. The included registries and studies examined 9 types of HF -HFmEF [25], HFpEF [25,35], HFrEF [18,23,25,32,33,[35][36][37][38][39][40], high output HF [23], hypertensive HF [18,23,26,48], ischemic HF [34,41], right HF [18,23], systolic HF [42][43][44][45][46], and thyrotoxic HF [27][28][29][30][31]. The prevalence of AF across these nine HF types varied significantly.…”

Clinical profile of thyrotoxicosis and related cardiovascular morbidities among patients attending endocrine outpatient department in a tertiary care centre

“…A similar result was seen in study conducted by Baladi et al where rate of atrial fibrillation was higher (p value <0.02) in above 30 years of age patients. 27 This study reports that tachycardia was observed in 47.12% of patients with Graves's disease. A similar study conducted by Shetty et al reported 61.3% of patients with Grave's disease having tachycardia.…”