“…About half of them have high output heart failure with normal ventricular ejection fractions and associated with coexisting atrial fibrillation (2) . The main manifestations of thyrotoxic cardiomyopathy are heart rhythm disturbances, usually atrial fibrillation (3) , left ventricular hypertrophy (4) , pulmonary hypertension and diastolic dysfunction (5) , dilation of the heart chambers and heart failure (6) . Reports show 1% occurrence of dilated thyrotoxic cardiomyopathy in patients with thyrotoxicosis, and one thirds of cases is irreversible (6) .…”