Low heart rate is not only a symptom, but may also indicate problems in other body parts. Generally, there are several main causes of low heart rate: 1. Low heart rate caused by certain diseases, such as influenza, depression, intracranial hypertension and hyperkalemia. 2. Low heart rate caused by taking certain drugs, such as reserpine, morphine, quinidine, anesthetics, etc. 3. Cardiovascular diseases that cause low heart rate, such as acute myocardial infarction, myocarditis and familial sinus bradycardia, etc. Patients with a low heart rate should be careful not to take drugs that lower the heart rate in their daily life, and take drugs that raise the heart rate if necessary. If the patient’s heart rate is below 40 beats per minute, a pacemaker may need to be implanted to effectively raise the heart rate by external force.