Therapeutic Research

Abstract

We report a case of subcutaneous implantable cardioverter defibrillator（S –ICD） malfunction. The case was a 48–year –old –man. He has been on maintenance dialysis since he was 44 years old. The patient was cardiopulmonary arrest at the last treatment of hemodialysis, recover to sinus rhythm for cardiopulmonary resuscitation and twice Automated External Defibrillator. We planned to implant a S –ICD as a secondary prevention. Preoperative screening confirmed the device was compatible with primary, secondary, and alternate polarities, and implantation was possible. The S–ICD（EMBLEMTM S–ICD, Boston Scientific） implantation was performed. The sensing polarity was set to the secondary due to the highest QRS –wave amplitude, and the T –wave the low amplitude. On the 5th day after the S –ICD implantation, the patient was discharged, only after confirming there were no changes in the amplitude. S –ICD potentials were confirmed over time by remote monitoring. However, after 3 months, the SMART Pass was turned off because the low amplitude QRS –wave. Fourth days after the SMART Pass was turned off, inappropriate therapy occurred at the end of hemodialysis. The waveforms for each sensing polarity were checked in the supine and seated positions. The automatic set up of the S –ICD selected the alternate sensing polarity, however we selected the primary polarity. Because the amplitude of the T –wave was low. Three months after the sensing polarity change, the SMART Pass has turned OFF, but to date, there has been no T –wave oversensing and inappropriate therapy. Since low amplitude QRS–wave in hemodialysis patients can be caused by various factors, inappropriate therapy activation could be avoided by checking the waveforms and setting sensing polarity appropriately.