Cardiac risks of hyperthyroidism in the elderly.

The importance of cardiovascular system involvement in hyperthyroidism has been recognized for many years. In the elderly patient, often with mild but prolonged elevation of plasma thyroid hormones, symptoms and signs of heart failure and complicating atrial fibrillation (AF) may dominate the clinical picture and mask the more classic endocrine manifestations of the disease. Impaired cardiopulmonary function and exercise capacity, significantly more marked in older patients, is observed in hyperthyroidism. Thyrotoxicosis can aggravate pre-existing heart disease and can also lead to AF, congestive heart failure, or worsening of angina pectoris. Regarding the high incidence of AF in older patients with hyperthyroidism, it is also important to detect subclinical hyperthyroidism in older patients with AF, thus warranting the measurement of the serum thyrotropin (TSH) concentration for early recognition and treatment. Most cardiac abnormalities return to normal once a euthyroid state has been achieved, although AF may persist in a minority. Optimal treatment requires rapid and definitive antithyroid therapy. Furthermore, anticoagulation is recommended for thyrotoxic patients with AF older than 50 years, those who have histories of previous emboli, hypertension, or with echocardiographic evidence of left atrial enlargement and/or myxomatous valves.