[A case of myxedema heart with serial endomyocardial biopsy].

We report a case of middle-aged woman with myxedema heart who presented congestive heart failure due to myocardial damage caused by myxedema, and showed reversible and irreversible myocardial change proven by serial endomyocardial biopsy. She was admitted to our hospital because of facial, peripheral edema and dyspnea. On admission, chest X-P revealed severe cardiomegaly (CTR 70%) and bilateral pleural effusion. Electrocardiogram showed low voltage. Echocardiogram and chest CT revealed a large amount of pericardial effusion. No significant stenosis was observed on a coronary arteriogram. Laboratory data showed elevated TC, CPK, LDH values and immunological test indicated high titer of thyroid test and microsome test. Thyroid function test revealed primary hypothyroidism with low T3, low T4 and high TSH levels. Replacement therapy for hypothyroidism in addition to digitalis and diuretics++ has been started. Seven months after initial evaluation, this therapy has resulted in dramatic clinical improvement. Transvenous right ventricular endomyocardial biopsy demonstrated vacuolated degeneration on admission and improvement of vacuolated degeneration with a slight degree of fibrosis after therapy. This pathological finding suggests that myxedema heart is able to produce both reversible and irreversible myocardial damage.