[Reversible dilated cardiomyopathy related to hyperthyroidism].

Heart failure is one of the most known complications of hyperthyroidism, more commonly high-output heart failure, but some patients may develop dilated cardiomyopathy with low ejection fraction. We report a 35-year-old man, with hyperthyroidism, atrial fibrillation, and severe heart failure with 43% of ejection fraction. After the definitive treatment of the hyperthyroidism with radioiodine, heart failure was reverted, with symptomatic improvement and echocardiographic normalization including a normal ejection fraction (69%).