[Reversible thyrotoxic cardiomyopathy--report of three cases].

Three patients with thyrotoxicosis, atrial tachyarrhythmia and congestive heart failure despite successful treatment of hyperthyroidism revealed atrial fibrillation/flagellation and left ventricular systolic dysfunction. Congestive heart failure resolved and left ventricular systolic function normalized only after successful cardioversion to sinus rhythm. In some patients treated for hyperthyroidism, achievement of euthyroid state is not by itself sufficient to reverse left ventricular failure. Improvement after successful reversion of atrial tachyarrhythmia suggest its essential role in pathogenesis of thyrotoxic cardiomyopathy.