Heart failure refers to the condition in which the heart's pumping function is relatively or absolutely insufficient, resulting in a series of symptoms. Patients may exhibit symptoms such as chest tightness, shortness of breath, difficulty breathing, and sometimes even cyanosis of the lips. Severe cases can lead to sudden death. Tachycardia and bradycardia are only due to disturbances in the patient's cardiac conduction system, causing the heart rate to accelerate or slow down. If the patient's heart function is good, the majority can compensate. However, prolonged tachycardia or prolonged bradycardia can potentially lead to heart failure. Therefore, heart failure is different from tachycardia or bradycardia.