Cardiac resynchronization therapy (CRT) device replacement considerations: upgrade or downgrade? A complex decision in the current clinical setting.

There are limited data about the management of patients presenting for elective generator replacements in the setting of previously implanted cardiac resynchronization therapy (CRT) devices that are nearing end-of-life. The individual patient's clinical status and concomitant morbidities may evolve so that considerations may include not only replacement of the pulse generator, but also potentially changing the type of device [e.g. downgrading CRT-defibrillator (CRT-D) to CRT-pacemaker (CRT-P) or ICD or upgrading of CRT-P to CRT-D]. Moreover, the clinical evidence for CRT-D/CRT-P implantation may change over time, with ongoing research and availability of new trial data. In this review we discuss the ethical, clinical and financial implications related to CRT generator replacements and the need for additional clinical trials to better understand which patients should undergo CRT device downgrading or upgrading at the time of battery depletion.