**4. Summary/Conclusion**

The currently available literature reveals that patients with adequate ICD therapy prior elec‐ tive ICD replacement have approximately 3-fold higher risk to receive adequate ICD interven‐ tion thereafter compared to patients without prior adequate ICD therapy. However, a significant number of patients without adequate ICD therapy prior elective device replace‐ ment will receive adequate ICD intervention thereafter too. In this patient population it is ex‐ pected that approximately every 5th with secondary and every 7th with primary prevention will receive adequate ICD therapy within 3 years following elective device replacement. Pa‐ tients who present at poor clinical status with more advanced stages of heart failure, especially with advanced NYHA classes (≥2), as well as patients with secondary prevention indication are at higher risk for adequate ICD therapy in long-term follow-up. No predictive factors for lower probability of ICD therapy could be identified for patients without adequate ICD therapy prior device replacement. Hence, ICD replacement appears still necessary in these patients. Risks of ICD therapy should not be underestimated but the weight of evidence for long-term benefit based on the incidence of ventricular arrhythmias with subsequent adequate ICD therapy sup‐ ports the continuing use of ICD therapy for patients with adequate ICD indication. Neverthe‐ less, through an intensive training of physicians in ICD-implantation, device replacement, programming, and aftercare of ICD patients, as well as the use of newer SVT discrimination and lead monitoring algorithms the rate of potential risks can be reduced substantially.
