Single-coil Subcutaneous Defibrillating Array

General Considerations

• The goal of an Implantable cardiac defibrillator (ICD) is to deliver a defibrillating shock high enough to exceed the defibrillation threshold
• Some patients have a high defibrillation threshold so that there is not an adequate safety margin between the defibrillation threshold and the maximum available output of the device
• That problem can be solved in many cases with the insertion of an additional intravascular defibrillating coil, but that determination has to be made in most circumstances at the time the original implantation procedure
• It is possible, however, to insert additional subcutaneous lead arrays after the original device is implanted which can reduce the defibrillation threshold and therefore increase the safety margin
• The array is tunneled subcutaneously in the left lateral chest
• It may consist of one or more electrodes

 
Single-coil Subcutaneous Defibrillator Lead. In addition to the patient's intravascular lead, there is a subcutaneously placed lead in the left lateral chest wall that extends into the posterior chest wall (white arrows)

The subcutaneous array: a new lead adjunct for the transvenous ICD to lower defibrillation thresholds. Higgins SL1, Alexander DC, Kuypers CJ, Brewster SA. Pacing Clin Electrophysiol. 1995 Aug;18(8):1540-8.

Implantation of additional subcutaneous array electrode reduces defibrillation threshold in ICD patients – preliminary results. Maciej Kempa,corresponding author Szymon Budrejko, Łukasz Drelich, Tomasz Królak, Grzegorz Raczak, and Dariusz Kozłowski. Arch Med Sci. 2013 Jun 20; 9(3): 440–444.