The LivaNova VNS Therapy System, used for Vagus Nerve Stimulation (VNS), consists of an implantable VNS Therapy generator, lead, and external programming system used to change stimulation settings. The generator is an implantable, multi-programmable pulse generator that delivers electrical signals to the vagus nerve through the lead. The generator is housed in a hermetically sealed titanium case and is powered by a single battery. Electrical signals are transmitted from the generator to the vagus nerve by the lead. The lead and the generator make up the implantable portion of the VNS Therapy System. The VNS Therapy Programming System includes a computer pre-installed with VNS Therapy programming software and a programming wand. The physician uses the programming system to read and change generator settings. The Model 1000 Generator was commercially approved for distribution in the U.S. on October 3, 2017 via PMA P970003/S210.

Lead impedance values reported by the affected VNS generator will be higher compared to those reported by previous models. This is due to a change in the timing of when affected VNS generator takes the lead impedance measurement during diagnostic testing. As a result, normal impedance ranges for the affected VNS generator have shifted relative to the existing thresholds of 600 - 5300 Ohms defined in labeling and as present in the programming software.

On 11/16/18, Medical Device Correction notices were mailed to treating and implanting physicians. The notice informed physicians that as indicated in the Physician's Manual, high lead impedance (greater-than-or-equal-to 5300 Ohms), in the absence of other device-related complications, is not an indication of a lead or generator malfunction. Existing recommendations, as described in the Physician's Manual, should still be followed. This will not impact the performance of the device, including the battery longevity and the ability to safely deliver therapy. The issue presents a risk of unnecessary surgery. Surgical interventions where high impedance could not be conclusively identified as being caused by a system malfunction or connector pin insertion issue have occurred in 0.24% of the potentially affected device population. Any patient implanted with a Model 1000 generator could potentially be affected by this issue. Patients implanted with 2.0 mm electrode leads (i.e. Model 30X-20) have a higher possibility of being affected by this issue than those patients implanted with 3.0 mm electrode leads (i.e. Model 30X-30), as the greater surface area of the 3.0 mm leads generally results in lower overall impedance results. Actions to be taken by the Physician 1. Continue to monitor patients and perform diagnostic testing at each visit. Information and recommendations regarding high and low impedance thresholds can be accessed in the VNS Therapy Physician's Manual If lead impedance is reported at, or above, the high impedance threshold (greater-than-or-equal-to 5300 Ohms): a. New implant patients: Perform an anteroposterior (AP) and lateral chest and neck X-ray and mail to Clinical Technical Support for X-ray review to assess proper lead pin insertion. b. Replacement patients: Perform an AP and lateral chest and neck X-ray and mail to Clinical Technical Support for X-ray review to assess proper lead pin insertion and for potential lead breaks. c. Contact