Association of daily rhythm monitoring parameters with thyroid hormone levels
in patients with coronary heart disease and primary overt hypothyroidism

Abdul Rahman Muneer, Cardiologist, Kerala Institute of Medical Sciences Hospital, Trivandrum, Kerala (India); postgraduate student, Irkutsk State Medical University (1 Krasnogo Vosstaniya street, Irkutsk, Russia), dr.reenum@gmail.com
Govindan Vijayaraghavan, Candidate of medical sciences, professor, Vice-President of Kerala Institute of Medical Sciences, Kerala Institute of Medical Sciences Hospital, Trivandrum, Kerala (India), drvijaraghavan@gmail.com 
Andrey S. Ankudinov, Candidate of medical sciences, assistant of the sub-department of simulation technologies and emergency medical care, Irkutsk State Medical University (1 Krasnogo Vosstaniya street, Irkutsk, Russia), andruhin.box@ya.ru
Aleksey N. Kalyagin, Doctor of medical sciences, professor, head of the sub-department of propaedeutics of internal diseases, Irkutsk State Medical University (1 Krasnogo Vosstaniya street, Irkutsk, Russia), akalagin@yandex.ru 

Background. The role of primary hypothyroidism during cardiovascular pathologies is actively discussed in the literature. There is an evidence of the increase in the frequency of cardiac arrhythmias in such patients compared with patients without hypothyroidism. The purpose of the study is to compare the daily rhythm indicators between patients with primary manifest hypothyroidism and coronary heart disease (CHD) and patients with CHD without hypothyroidism, as well as to analyze possible associations of these indicators with thyroid hormone levels. Materials and methods. A single-stage crosssectional study was conducted with the participation of 90 patients with coronary artery disease and primary manifest hypothyroidism and 150 patients with coronary artery disease without hypothyroidism. A comparative assessment of the daily rhythm indicators of the examined groups and an assessment of possible associations of these indicators with thyroid hormone levels were carried out. Results Statistically significant differences were revealed in the average maximum daily values of heart rate (HR), the average number of supraventricular extrasystoles (SVES) per day, the average number of episodes of ST segment depression greater than 0.1mV and the average number of episodes of ST depression lasting more than 80 ms. Statistically significant moderate direct correlations with thyroidstimulating hormone (TSH) were also found with parameters such as the average number of episodes of ST depression greater than 0.1mV (r=0.3; p=0.001), the average number of SVES (r=0.2; p=0.04) and the average maximum daily heart rate (r=0.1; p=0.003). Statistically significant moderate inverse correlations of free thyroxine (T4) with the average number of episodes of ST depression per day (r=0.1; p=0.009) lasting more than 80 ms and the average maximum daily heart rate (r=0.1; p=0.001) were found.Conclusions. Patients with coronary heart disease and primary manifest hypothyroidism have significantly worse indicators of daily heart rate parameters and associations with thyroid hormones. 

 coronary heart disease, primary manifest hypothyroidism, thyroid hormones

Muneer A.R., Vijeyraghavan G., Ankudinov A.S., Kalyagin A.N. Association of daily rhythm monitoring parameters with thyroid hor-mone levels in patients with coronary heart disease and primary overt hypothyroidism. Izvestiya vysshikh uchebnykh zavedeniy. Povolzhskiy region. Meditsinskie nauki = University proceedings. Volga region. Medical sciences. 2022;(3):29–41. (In Russ.). doi:10.21685/2072-3032-2022-3-3