Multiple shocks after upgrade of an implantable cardioverter-defibrillator to a cardiac resynchronization therapy-defibrillator device

Inappropriate shocks from implantable cardioverter-defibrillators (ICDs) may occur for many reasons. Inappropriate shocks are not simply painful inconveniences for patients; they also may result in the need for further operative procedures, and sometimes even death. Herein, we report the case of a patient who after upgrade of an ICD to a cardiac resynchronization therapy-defibrillator device (CRT-D), returned with multiple shocks due to altered sensing and defibrillation polarities that resulted from actual physical reversal of the distal (-) and proximal (+) lead terminals in the header of the device.