Yet when the implant age is beyond 4 years the longevity is much improved. End-of-service is now not reached for 50% of generators until 5.5 to 6 years. However, this remains worse than the longevity of atrial epicardial electrodes. Therefore the limiting factor in the interval between pacemaker interventions in children requiring epicardial implants is generator longevity not electrode longevity irrespective of implant age.