Tachycardia is a common type of heart rhythm disorder (arrhythmia) in which the heart beats faster than normal while at rest. It's normal for your heart rate to rise during exercise or as a physiological response to stress, trauma or illness (sinus tachycardia). But in tachycardia (tak-ih-KAHR-dee-uh), the heart beats faster than normal in the upper or lower chambers of the heart or both while at rest. Your heart rate is controlled by electrical signals sent across heart tissues. Tachycardia occurs when an abnormality in the heart produces rapid electrical signals that quicken the heart rate, which is normally about 60 to 100 beats a minute at rest. In some cases, tachycardia may cause no symptoms or complications. But if left untreated, tachycardia can disrupt normal heart function and lead to serious complications, including: Heart failure Stroke Sudden cardiac arrest or death Treatments, such as drugs, medical procedures or surgery, may help control a rapid heartbeat or manage