Combined Use of a True‐Bipolar Sensing Implantable Cardioverter Defibrillator in a Patient Having a Prior Implantable Spinal Cord Stimulator for Intractable Pain

Reported is a case involving a patient with a previously implanted spinal cord stimulator (SCS) who presented for an implantable cardioverter defibrillator (ICD). The SCS device was located in the left lower abdominal quadrant with a stimulation electrode array placed on the dorsal aspect of the spinal cord at the T-11 thoracic level. Interaction testing demonstrated that the biopolar sensing transvenous ICD system (Medtronic 7221 Cx PCD) did not detect the stimulator's output at burst rates ranging from 20-130 pulses/s, even with the ICD set to its maximum sensitivity of 0.15 m V and the stimulator programmed to the highest patient tolerated output combinations of 5 V, 0.45 ms in the bipolar configuration and 3 V, 0.45 ms in the unipolar (i.e., case-electrode) configuration.