Discussion
To date, there is a paucity of reported cases of EMI interaction between ICDs and LVADs, with the first case reported in 2006.2Six cases have reported an interaction between ICDs and the HeartMate II, resulting in the inability to interrogate and program the ICD, inappropriate shocks, and pacing inhibition (St. Jude Medical and Sorin being the most commonly affected ICDs).2-7 Five other case reports show interactions between HeartWare and ICDs presenting as pacing inhibition or inappropriate shocks.8-12 With HeartMate III, 7 cases of ICD EMI have been reported, resulting in communication failure in 6 cases and over-sensing LVAD noise signal in one case. 13-15
Several strategies have been proposed to enable successful communication, interrogation, and reprogramming of an ICD in the setting of EMI with an LVAD:
  1. The HeartMate III user’s manual recommends that prior to implanting an ICD or pacemaker into a HeartMate III patient, the device to be implanted be placed in close proximity to the LVAD pump (approximately 10 cm) and assure that telemetry communication is established. This approach may be the easiest to confirm the safe distance between the ICD and the LVAD without requiring special equipment and can be performed in office settings. However, this is only a screening technique and its effectiveness may be limited after device implant. If a patient receives a HeartMate III pump and has a previously implanted device that is found to be susceptible to electromagnetic interference, the ICD or pacemaker device should be replaced with one that is not prone to programming interference.
  2. A Faraday cage is an enclosure used to block electromagnetic fields that can be created temporarily with conductive material such as metal sheets, mesh or more conveniently, a cast iron pan/sheet externally positioned to isolate the ICD device from the field created by the LVAD motor. Creating a Faraday cage has been shown to be useful in isolating both devices and thus eliminating potential communication interference.3
  3. Altering the operating frequency of the LVAD or ICD may theoretically eliminate EMI between the two devices. The operating frequency of an ICD is fixed and only altered by changing to another manufacture’s pulse generator. This comes with procedural risks, most notably pocket infection. LVAD generated EMI, determined by motor speed, can be adjusted to below 1300 rpm or above 11,000 rpm to establish ICD communication.4 However, extreme alterations to the LVAD motor may cause hemodynamic compromise and therefore, is not a viable option, in general.
Currently, there are no optimal solutions eliminating EMI interactions between LVADs and ICDs after device implantation. Therefore, selection of the combination of available LVAD and ICD devices must be carefully considered before implantation of either device. Further research is needed to assess, interpret and prevent EMI interaction between ICDs and third-generation, magnetically driven LVADs.