Heart failure and dilated cardiomyopathy associated with severe longstanding untreated hypothyroidism.

Thyroid hormones have many effects on the heart and vascular system. Although cardiac output is reduced in hypothyroidism, heart failure is relatively rare because there is a lower demand for peripheral oxygen delivery. Hypothyroidism may also result in accelerated atherosclerosis and coronary artery disease. We report the case of a 55-year-old man with severe heart failure associated with severe longstanding untreated hypothyroidism. The patient was admitted for shortness of breath and chest pain. On presentation, signs and symptoms of severe hypothyroidism and heart failure were noticed. The electrocardiogram showed sinus bradycardia and ischemia. Thyroid stimulating hormone was extremely elevated and thyroid hormone levels were undetectable. A cardiac ultrasonography exam revealed abnormalities of the left ventricular dimensions and function consistent with dilated cardiomyopathy. Coronary angiography showed severe multivessel disease. Coronary by-pass was deemed necessary, but surgery was postponed because of severe heart failure. After an increasingly downhill clinical course, the patient died, eight month after his initial presentation, owing to severe heart failure. This patient represents an example of an overlooked diagnosis of severe hypothyroidism, rarely encountered nowadays, leading to dramatic consequences.