If an electrocardiogram shows that a patient has sinus bradycardia, there is usually a physiological factor or a pathological cause. For physiological factors, it is not a serious condition, such as in elderly people or people who have been involved in sports for a long time, in which case sinus bradycardia can occur. However, some pathological factors cause sinus bradycardia, which is a serious condition that can lead to malignant arrhythmias and eventually to sudden cardiac death if left untreated. For pathologic bradycardia, for example, patients with increased vagal tone, such as acute meningitis, cerebral hemorrhage, or intracranial tumor occupancy triggers increased intracranial pressure, which reflexively triggers sinus bradycardia. In addition, cardiogenic diseases are often found in coronary artery disease, severe angina pectoris, myocardial cell damage, and pathological sinus node syndrome, which can also lead to sinus bradycardia. Therefore, once the heart rate becomes too low, usually at 40 beats per minute or even below, it must be treated aggressively, otherwise it is prone to serious complications.