Safe use of repetitive transcranial magnetic stimulation in patients with implanted vagus nerve stimulators

Vagus nerve stimulation (VNS) and repetitive transcranial stimulation (rTMS) devices are FDA cleared for therapeutic use in treatment resistant depression. Since VNS systems have ferromagnetic components and large-scale safety testing has not been done, the implanted VNS device is considered a contraindication for rTMS therapy. This contraindication should not be considered absolute, as VNS components typically lie outside the electromagnetic field generated by an rTMS treatment coil. We solicited information from clinicians at several academic medical centers through an informal survey about their use of rTMS for depressed patients with implanted VNS systems, and reviewed relevant safety issues with one rTMS device manufacturer. rTMS clinical practices may use special consent procedures and take additional precautions to enhance safety in these situations. Specific recommendations are provided for minimizing risks (heating or movement of VNS components and unintended change in VNS stimulation parameters) when delivering rTMS to patients with implanted VNS systems.