Tachycardia can increase the risk of sudden death. Tachycardia is defined as a heart rate greater than 100 beats per minute, and whether sudden death can occur depends on the severity of the tachycardia and its specific cause. There are many types of tachycardia, the most common being atrial tachycardia, atrial flutter, atrial fibrillation, etc. Such tachycardia usually does not lead to death, but if it is not treated aggressively and is frequent, it may lead to other complications, resulting in decreased cardiac function and, in severe cases, sudden death. In addition, ventricular tachycardia or ventricular fibrillation is more serious because the ventricles do not fill and contract properly during ventricular fibrillation, which can lead to a lack of blood supply to the body, thus endangering life and requiring immediate treatment such as electrical defibrillation. There is also a physiological tachycardia, such as coffee, strong tea, alcohol and mood swings, if there are no other symptoms, pay attention to rest, avoid the above triggering factors can be, generally will not occur sudden death. If tachycardia occurs, you should go to the hospital for examination and active symptomatic treatment. In daily life, you should pay attention to a healthy diet, adjust your emotions, and avoid bad habits such as smoking, alcoholism, and staying up late.