If a patient experiences sudden tachycardia accompanied by hand tremors, there are several possibilities: 1) Hypoglycemic reaction, especially for patients with a history of diabetes mellitus, sudden tachycardia accompanied by palpitations, hand tremors, sweating, dizziness, and hunger is a typical clinical symptom of hypoglycemic reaction.2) Patients with a history of thyroid insufficiency or hyperthyroidism may also experience sudden palpitations accompanied by hand tremors when they have an overactive thyroid. 3) Patients with heart disease experience the above symptoms and consider whether acute coronary syndromes and arrhythmias are present.4) Patients with cardiac disease experience the above symptoms. Palpitations, accompanied by hand tremors, are typical clinical symptoms of hypoglycemic reaction. 3. Patients with heart disease who experience the above symptoms should be considered for acute coronary syndrome and arrhythmia.