Symptoms of hyperthyroid heart disease include arrhythmia, heart enlargement, heart failure and angina pectoris. 1. Arrhythmia: The most common arrhythmias of hyperthyroidism include sinus tachycardia, atrial premature beats, paroxysmal tachycardia, ventricular flutter and atrial fibrillation, the most common of which is atrial fibrillation. 2. Enlarged heart: hyperthyroidism and enlarged heart. Long-term untreated hyperthyroidism can lead to significant changes in the shape of the heart, including enlarged atria or ventricles, increased heart weight, cardiomyocyte hypertrophy, and widening of the myocardial fiber gap. 3. Angina pectoris and myocardial infarction: The low incidence of angina pectoris in hyperthyroid heart disease is mainly due to the relative lack of blood supply to the coronary arteries. Chest or chest tightness is more common and myocardial infarction is less common. Patients should not overexert themselves, seek timely medical examination, and follow the doctor’s instructions for treatment.