Rare Presentation of Cardiac Tamponade in a Patient With Subclinical Hypothyroidism.

Cardiovascular effects of hypothyroidism include bradycardia, diastolic hypertension, atrial fibrillation, prolonged QT interval leading to torsades de pointes, varying degrees of AV block, accelerated coronary artery disease, and pericardial effusion. Cardiac tamponade is rare in patients with hypothyroidism because of pericardial distensibility and slow accumulation of fluid. The amount and rate of accumulation of pericardial effusion are related to the severity of hypothyroidism. Though rare, significant pericardial effusion can be a manifestation of subclinical hypothyroidism.