External cardioversion in patients with implanted cardiac devices: is there a problem?

摘要

As the indications for implantable cardiac devices [pacemakers, cardioverter-defibrillators (ICDs), and cardiac resynchronization systems (CRT)] have been extended over the last decade, the need for elective external cardioversion (ECV) in patients with such devices and concurrent atrial fibrillation (AF) has also increased. In addition, the overall requirement for ECV has also been extended by the increasing age of the population in most developed countries and a more aggressive approach to the management of recent-onset and haemodynamically compromising AF. The use of ECV in patients with implanted devices has long been a cause for concern with regard to the potential for adverse effects on the generator and/or leads, with the result that this simple and effective therapy may have been delayed or even denied to some patients. These concerns were largely fuelled by a number of reports in the 1970s and 1980s suggesting the potential for device interference or lead failure. Devices implanted within the last decade, however, are considerably more sophisticated, more likely to use bipolar lead configurations, and better protected against external interference than those of the period from which these reports arose, leaving the question of safety in patients with modern implantable devices open. In addition, ECV has evolved over recent years with the development of equipment able to deliver biphasic shocks resulting in an increased efficacy and lower energy requirements.