Implantable cardioverter defibrillators (ICD) prevent recurrent arrhythmic death in sudden death survivors or may prevent its development in physically active patients with an underlying risk for malignant ventricular arrhythmias. Although ICD do not substitute for the usual recommendations to refrain from intensive or competitive exercise because of an underlying arrhythmic disorder, they often provide a means for safe continuation of mild to moderate recreational sports activity. Long-term quality of life will be highly dependent on the prevention of inappropriate ICD shocks. This requires the choice of a durable lead and device system, careful programming tailored to the characteristics of the patient's physiologic and pathologic heart rhythms, preventive bradycardic medication, and guided rehabilitation with psychologic counseling.