Despite major advances in the understanding of mechanisms, better diagnostic methods and a wide array of new modes of therapy, management of cardiac arrhythmias continues to be a challenge. Because of possible deleterious effects of antiarrhythmic therapy, the decision about when and how to treat should be weighed carefully with emphasis on symptoms and the prognostic significance of the arrhythmia. When possible, the high risk patient should be referred to a center where expertise and diagnostic and therapeutic possibilities allow optimal treatment.