Thyroid storm and myxoedema: two reversible causes of acute heart failure.

Cardiovascular signs and symptoms can prevail in both hypothyroidism and hyperthyroidism. Case 1: 30-year-old female with acute right heart failure as first manifestation of Graves' disease. It illustrates some of its cardiovascular complications, particularly pulmonary hypertension, tricuspid regurgitation, atrial fibrillation, mitral valve prolapse and mitral regurgitation. Case 2: 83-year-old-man with a severe primary hypothyroidism/myxoedema crisis presented to emergency department with extreme bradyarrhythmia with hemodynamic impact and heart failure signs, which led to implantation of definitive pacemaker. Thyroid disorders are treatable entities and most cardiovascular changes are reversible. Early diagnosis is mandatory and can avoid severe complications and, eventually, invasive therapeutics interventions. Pulmonary hypertension and acute heart failure, especially in young adults, should be screened for underlying hyperthyroidism.