Clinical research: Implantation of additional subcutaneous array electrode reduces defibrillation threshold in ICD patients - preliminary results

• Published in: Archives of medical science Vol. 9; no. 3; p. 440
• Main Authors: Kempa, Maciej, Budrejko, Szymon, Drelich, Lukasz, Królak, Tomasz, Raczak, Grzegorz, Kozlowski, Dariusz
• Format: Journal Article
• Language: English
• Published: Poznan Termedia Publishing House 01.05.2013
• ISSN: 1734-1922; 1896-9151
• DOI: 10.5114/aoms.2013.35480

Introduction: Among the recipients of implantable cardioverter-defibrillators (ICDs), there is a group of patients in whom the defibrillation threshold (DFT) is too high to enable a sufficient safety margin between the DFT and the maximal available output of the device. The aim of the study was to investigate the ability of an additionally implanted single-coil subcutaneous array electrode to reduce the DFT in such patients. Material and methods: Medtronic 6996SQ electrode was implanted in 15 patients selected from our follow-up group of 741 ICD patients: 10 of them had insufficient post-implant DFT safety margin, and 5 had ineffective first maximal energy shock as recorded by the device. In 6 cases the patients had CRT-D devices, in 5 cases - dual-chamber ICDs, and in 4 cases - single-chamber ICDs. In all patients but one the defibrillating electrode was single-coil. In one patient it was dual-coil. The underlying disease was coronary artery disease in 10 patients, dilated cardiomyopathy in 4 patients and hypertrophic cardiomyopathy in 1 patient. Results: The subcutaneous electrode was successfully implanted in all the patients qualified for the procedure. No technical issues or perioperative complications were observed. Mean DFT was reduced from 33.3 ±4.1 J before the procedure to 25.3 ±4.4 J after the implantation procedure (p < 0.01). Conclusions: Our results show that the use of a single-coil subcutaneous electrode to reduce the DFT is a safe and effective procedure. Further studies are necessary to confirm these results.