Cardiac arrhythmia is an abnormal heart rhythm. It can cause the heart to beat too fast, too slow, or irregularly. It can also cause the heart to pause or stop beating altogether. Cardiac arrhythmia can be caused by a variety of factors, including heart disease, medications, electrolyte imbalances, and other medical conditions. Treatment for cardiac arrhythmia depends on the type and severity of the arrhythmia. Treatment may include lifestyle changes, medications, or medical procedures.