[Cardiovascular effects of hypothyroidism]

The clinical presentation of cardiac symptoms related to hypothyroidism is only rarely observed nowadays due to early diagnosis of hypothyroidism by easily available thyroid-stimulating hormone assays. A measurable abnormality of the left ventricle is the lengthened duration of contraction and relaxation, normalizing after restoration of euthyroidism. The ejection fraction and cardiac reserve are only slightly diminished in hypothyroidism. There is reversible diastolic disfunction. Pericardial effusion is a rare phenomenon. Diastolic hypertension due to hypothyroidism is the most frequent cause of endocrine hypertension. The relation between accelerated atherosclerosis and hypothyroidism is not definitively proven. Patients below age 65 and without cardiac risk factors can probably be treated with a full replacement dose of levothyroxin from the beginning. There is no increased risk of percutaneous transluminal coronary angioplasty or coronary artery bypass graft procedure in hypothyroid patients, either during or after the intervention.