Recognition and management of cardiovascular disease related to thyroid dysfunction.

Hypothyroidism and hyperthyroidism are both associated with clinically significant cardiovascular derangements. In hypothyroidism, these include pericardial effusion, heart failure, and the complex interrelationship between hypothyroidism and ischemic heart disease. Cardiovascular disorders associated with hyperthyroidism include atrial tachyarrhythmias, mitral valve dysfunction, and heart failure. Although these usually occur in individuals with intrinsic heart disease, thyroid dysfunction alone rarely causes serious but reversible cardiovascular dysfunction. Patients with commonly encountered cardiac disorders, e.g., idiopathic cardiomyopathy and atrial fibrillation, should be screened for potentially contributing subclinical thyroid diseases. In patients with heart failure and hypothyroidism, initial management should focus on diagnosis and optimal management of any primary cardiac disease, whereas in hyperthyroidism, aggressive measures to control excess thyroid hormone action should generally have the highest priority.