Discussion
It is a well-known fact that the thyroid hormones play a crucial role over the development and function of the cardiovascular system. The hormones thyroxine (T4) and tri-iodothyronine (T3) exert their effects through cellular receptors and non-genomic pathways on myocardial contractility and oxygen consumption, cardiac output and rhythm, systemic vascular resistance and blood pressure.2,4 Hence, when thyroid dysfunction is known or clinically suspected, a cardiovascular disease or risk should be investigated. The Clinical Management Guidelines for Coronary Artery Disease for National Program for Prevention and Control of Diabetes, Cardiovascular Disease and Stroke5 recommends that blood samples should be sent for cardiac enzymes for diagnosis of acute coronary syndromes; hemogram, fasting blood glucose, blood urea, creatinine, and electrolytes for monitoring, and fasting lipid profile for secondary prevention. In spite of the known correlation and high prevalence of thyroid diseases in India, the thyroid functions are not specifically assessed. Clinical hypothyroidism is characterized by decreased levels of T3 and T4, and compensatory elevated levels of thyroid stimulating hormone (TSH). Apart from classical clinical symptomatology, hypothyroidism induces diastolic hypertension, bradyarrhythmias, increased atherogenicity, systemic inflammation, endothelial dysfunction and hypercoaguability.
