Cardiac arrhythmia is caused by abnormal excitation of the sinus node or excitation generated outside the sinus node, slow conduction, blockage or conduction through abnormal channels, that is, the origin and (or) conduction disorder of cardiac activity leads to abnormal frequency and (or) rhythm of heart beats. Cardiac arrhythmia is an important group of cardiovascular diseases. It can occur alone or in conjunction with cardiovascular disease. It can occur suddenly and cause sudden death, or it can continue to affect the heart and cause failure. The meaning of words such as "heart rhythm disorder" or "irregular heartbeat" focuses on rhythm disorders. Arrhythmia includes both rhythm and frequency abnormalities, which is more accurate and appropriate.