Antiarrhythmic medicines may be used to return an irregular
heartbeat (arrhythmia) to its normal rhythm, prevent an arrhythmia, or control
the heartbeat during an arrhythmia. These drugs work mostly by slowing the
heart rate or by helping the heart muscle tissue become stable.
Many antiarrhythmic medicines have side effects, and many interact with
other medicines. A person taking any of these medicines should talk often with
his or her doctor.