Hypothyroidism is common in adults, and in most cases, its clinical manifestations are subtle or absent altogether, with symptoms only presenting relatively late in thyroid gland failure [Chaker, 2022].  By that time, thyroid hormone deficiency may have already adversely affected blood pressure, heart rate and rhythm, myocardial contractility, endothelial function and atherogenic lipoprotein levels [Cappola, 2019]. This is not surprising, as thyroid hormones regulate key functions in the cardiac conducting system, cardiomyocytes, peripheral vascular smooth muscle and endothelium, and hepatocytes involved in lipoprotein metabolism [Jankauskas, 2021]. Thus, the clinical consequences of hypothyroidism can include hypertension (especially diastolic), bradycardia, heart failure, hypercholesterolemia and increased risk of atherosclerotic cardiovascular disease. In patients with overt hypothyroidism, levothyroxine therapy can have positive and clinically important effects on cardiovascular functions, except fixed atherosclerotic lesions [Garber, 2012]. In individuals with more common subclinical hypothyroidism, lower risks of cardiovascular events and death have been seen in levothyroxine-treated middle-aged adults compared with those untreated, but this effect is less clearly shown in the elderly [Razvi, 2012]. In this podcast, Professor Paul Ladenson will share his expert view on the association of hypothyroidism with the cardiovascular system and the selection of those patients who would benefit most from a restored euthyroid state.