Bradycardia is usually referred to as sinus bradycardia, the causes of which are as follows: 1, common in healthy young people, athletes and sleep state; 2, intracranial diseases, such as brain hemorrhage or brain tumors, etc.; 3, patients with severe hypoxia will also appear slow heart rate; 4, metabolic reduction, such as patients with severe malnutrition, hypothyroidism will also appear bradycardia; 5, jaundice, schizophrenia and other patients; 6, the use of some special drugs may also lead to bradycardia. 6, the use of certain special drugs may also lead to bradycardia, some of the drugs commonly used by cardiologists will also slow down the heart rate, such as beta-blockers, digitalis drugs; 7, patients with kidney disease combined with hypertension, will also occur sinus bradycardia; 8, primary sinus node lesions, the heart pacing function problems, will occur sinus bradycardia; 9, serious complications, such as myocardial infarction will occur when the sinus Bradycardia is caused by the blockage of blood to the pacing sinus node function, which leads to bradycardia in patients.