Cardiac arrhythmias are commonplace in the Western world and vary in their degree of seriousness from benign to life threatening. In general, arrhythmias may be managed in one of five ways: reassurance only, physical maneuvers, antiarrhythmic drugs, implantable electronic devices, and surgical or transvascular ablation. Treatment is designed to terminate ongoing arrhythmias, to prevent recurrence of arrhythmias, or to control the rate of the arrhythmia. Occasionally, the propensity to arrhythmia may be cured by abolition of the anatomic substrate for the arrhythmia. Which of these modalities and approaches to the management of cardiac arrhythmia will be chosen by the physician for any individual patient is very much dependent on the character of the arrhythmia and the patient's underlying disease.