Hyperthyroidism is short for hyperthyroidism. Hyperthyroid heart disease can be serious. Excess thyroid hormone can lead to tachycardia, increased cardiac contractility and increased blood output, resulting in increased cardiac load, increased myocardial oxygen consumption, and relative insufficiency of coronary blood supply, which can cause abnormal cardiac changes. Hyperthyroidism may lead to conditions such as enlarged heart, arrhythmia, congestive heart failure, angina pectoris or myocardial infarction, which can be life-threatening in severe cases. Usually, the above heart conditions will get better or improve significantly once the hyperthyroidism is under control. Patients with hyperthyroid heart disease should seek timely medical treatment and actively cooperate with professional doctors to avoid serious consequences.