Safety Advisories Regarding Boston Scientific Emblem S-ICD
On December 3, Boston Scientific announced three advisories related to its Emblem S-ICD. They address the potentials for battery depletion, device damage due to electrical shorting, and lead fracture.
On December 3, Boston Scientific announced three medical device advisories related to the Emblem S-ICD. Each advisory's key aspects are addressed below. The company is releasing these simultaneously since some devices could be affected by more than one of the 3 advisories. To determine if a device is affected in any of these advisories, you can enter the model/serial number on Boston Scientific's Device Lookup Tool.
- An Elevated Likelihood of a Low Voltage Capacitor Causing Accelerated Battery Depletion
Boston Scientific is expanding its August 2019 advisory to an approximate device population of 38,350 Emblem S-ICD active implants manufactured prior to August 2018 (Models A209 and A219) which have an elevated likelihood of a low voltage capacitor causing accelerated battery depletion. The capacitor was changed in August 2018 and devices made prior to the change are no longer available. The current estimate of premature battery depletion occurring in the expanded population is 3.7% which may be updated over time as additional device data is accrued. Based upon analyses from returned product with this behavior, 21 days of therapy are available after reaching ERI; Generators should be replaced within 21 days of reaching ERI. The company is currently developing software that will detect premature battery depletion behavior and deliver an alert.
- Events of Electrical Overstress (i.e. damage to the device caused by electrical shorting) During Delivery of High Voltage Therapy
In a subset of Emblem S-ICDs (Models A209 and A219) manufactured between May 2015 and December 2017, six (6) events of electrical overstress with electrical shorting during delivery of high voltage therapy have been confirmed. Although devices manufactured during this time frame are no longer available, there are currently 3,350 active implants. All six confirmed events either presented with alerts or were unable to be interrogated. In the event of an overstress event with electrical shorting which results in damage to the generator, a programmed defibrillation shock may not be delivered. There is no means to predict which of the affected 3,350 devices will experience electrical shorting. Patients with affected devices should be instructed to contact their physician whenever a shock is delivered since this occurs during high voltage therapy.
- Electrode Body Fractures at a Location Just Distal to the Proximal Sense Ring
Of the 47,000 Emblem S-ICD Subcutaneous Electrodes (Model 3501) distributed worldwide since 2017, there have been 27 reports of electrode body fractures at a location just distal to the proximal sense ring. A fractured lead will result in the inability to deliver high voltage therapy. For systems programmed in the Primary sensing configuration, the first indication of a fracture will be a high impedance alert with beeping tones once the fracture has occurred. The system runs an integrity test, which includes a lead impedance check, on a weekly basis; A fractured electrode may not be detected until the following integrity test. For systems programmed in the Secondary or Alternate sensing configuration, electrode fracture may be preceded by non-physiologic artifact that are stored as tachy episodes and can result in inappropriate shocks. Consideration can be given to changing the sensing configuration if adequate sensing can be demonstrated. The overall failure rate is 0.22% and the failure rate due to this mechanism specifically is 0.07% which is less than the recommended transvenous lead failure rate of 0.4% per the 2017 HRS Consensus document.
- Recommendations Common to All Three Advisories
- Monitor patients through LATITUDE patient management system per the 2015 HRS Consensus Statement on remote monitoring.
- Demonstrate and assess the patient's ability to hear the beeping alert in clinic
- Repeat beeper demonstration in patients not followed by LATITUDE after an MRI which can affect the beeper volume
- Remind patients to promptly call if they hear beeping tones
- Perform a device follow-up every 3 months either remotely or in person
HRS strongly encourages its members to become familiar with these 3 advisories and Boston Scientific's recommendations for following affected patients. A Dear Patient letter can also be found here. HRS also encourages providers to discuss these issues in a shared decision making fashion with their patients to determine the best course of action for each individual patient that is affected.
Adverse reactions or quality problems experienced with the use of this product should be reported to Boston Scientific or to the FDA MedWatch Safety Information and Adverse Event Reporting Program either online, by regular mail or by fax.