The role of thyrostatic agents in the treatment of chronic heart failure patients with comorbid coronary artery disease and thyrotoxicosis

Background: Thyroid dysfunction exerts a pronounced effect on the cardiovascular system, and, if comorbid with an existing cardiovascular disorder, may lead to a significant deterioration in the outcome, thus obviating the need for timely diagnosis and therapy optimization.Aim: To evaluate the effect of combination therapy, including thyrostatics, on the clinical symptoms of chronic heart failure (CHF), heart rate variability, NT-proBNP concentration, and structural and functional parameters of the left heart in patients with comorbid coronary artery disease (CAD) and thyrotoxicosis.Materials and methods: This open-label comparative study included 77 patients aged 45–65 years. The study group consisted of 36 patients with thyrotoxicosis, CAD and CHF II–III functional class, whereas the comparison group consisted of 41 patients with thyrotoxicosis without cardiovascular diseases. The patients were assessed clinically at baseline and after 6 months of therapy with addition of a thyrostatic, with tolerance to physical activity, measurements of NT-proBNP levels, 24-hour Holter monitoring, and echocardiography.Results: At 6 months of the combination therapy including a thyrostatic, with stable drug-induced euthyroidism, the patients in the group 1 showed an increase in the distance of a 6-minute walking test (p<0.001) and a decrease in CHF clinical symptoms. The incidence of heart rhythm disorders decreased (supraventricular extra systoles from 31% to 16%, ventricular extra systoles from 21% to 4%, atrial fibrillation from 32% to 23%; p<0.05), with a positive trend for spectral and temporal parameters of heart rate variability. The NT-proBNP level in patients with CAD, CHF and thyrotoxicosis decreased by 42.9% (p=0.001). During euthyrosis, echocardiography in the patients with ischemic CHF and concomitant thyrotoxicosis showed a significant increase in stroke volume (p=0.03), stroke ejection index (p=0.04), left ventricular ejection fraction (p=0.01), a decrease in the value of myocardial stress (p=0.02), and transmitral blood flow parameters (E/A, p<0.05). This indicates an improvement in systolic and diastolic left ventricular function after normalization of thyroid function.Conclusion: The inclusion of thyreostatics to the combination therapy and the achievement of euthyrosis have contributed to increased tolerance to physical activity, reduction of sympathetic activity level of the autonomic nervous system and frequency of heart rhythm disorders, reduced the NT-proBNP levels, improved systolic and diastolic left ventricular function in patients with ischemic CHF and concomitant thyrotoxicosi