If patients often have sudden tachycardia: 1. There are physiological causes and pathological factors. For physiological causes, such as patients in mental tension, fatigue, excessive stress, poor rest and sleep, or a lot of alcohol, strong tea and coffee, smoking, will cause sudden tachycardia to occur. For pathological factors, such as patients with cardiogenic diseases, such as unstable angina pectoris, severe arrhythmia, heart failure, acute myocarditis, etc., sudden tachycardia may occur. 2. For endocrine metabolic diseases, often in hyperthyroidism, hyperparathyroidism, hyperadrenocorticism may also be manifested. 3. For example, patients with cardiac neurosis may also have clinical symptoms.