Important Recommendations for Implantable Cardioverter-Defibrillators: Premature Battery Discharge

This document provides important recommendations for physicians regarding the risk of premature battery discharge in implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy defibrillators (CRT-Ds) manufactured by St. Jude Medical before May 23, 2015. It details the issue of lithium cluster formation leading to short circuits and premature battery depletion, outlines identification and management strategies, and provides patient guidance.

Date: October 10, 2016

Subject: Risk of premature battery discharge in implantable cardioverter-defibrillators.

St. Jude Medical is informing physicians about the risk of premature battery discharge associated with ICD and CRT-D devices manufactured before May 23, 2015. Affected models include Fortify™, Fortify Assura™, Quadra Assura™, Quadra Assura MPTM, Unify™, Unify Assura™, and Unify Quadra™.

Out of 398,740 devices sold globally, 841 returned devices showed signs of lithium material in the form of "clusters." In 46 of these devices, visible clusters formed bridges between the cathode and anode, causing a short circuit. Lithium cluster formation is a known phenomenon for this type of battery.

Premature battery discharge can occur within days. Two deaths have been reported, linked to the loss of defibrillation therapy due to premature battery discharge.

Mode and Identification of Premature Battery Failure

High-voltage devices (ICDs and CRT-Ds) that use a lithium-based battery chemistry are susceptible to lithium cluster formation during high-voltage charging. Depending on their location, these lithium clusters can cause a short circuit, leading to premature battery discharge. Our investigation indicates that in the event of a short circuit, battery discharge in these devices can occur within one day to several weeks, potentially rendering therapy delivery impossible.

Premature battery discharge, which may manifest as an Elective Replacement Indicator (ERI) or a deeper battery depletion, can be identified by physicians through remote monitoring or during in-person visits. Patients may be alerted to ERI by a vibration alert. Patients who do not feel the vibration alert may not be aware that their device has reached ERI. Therefore, recommendations include confirming the patient's ability to feel and recognize the vibration alert and reconfirming the use of remote monitoring to minimize periods without bradycardia and tachycardia therapy.

Assessment of Premature Battery Failure Frequency

Accurately assessing the frequency of premature battery failures is challenging due to potential underreporting of battery discharges in general and discharges caused by this specific failure mode that may go unrecognized.

Of the 398,740 devices sold worldwide, 841 (0.21%) returned devices showed signs of premature discharge associated with lithium clusters. Forty-six (46) devices worldwide showed clear signs of short-circuiting due to lithium clusters. Detailed information is provided in Table 2.

Currently, 349,852 affected devices are still implanted worldwide and are potentially at risk.

Recommendations for Patient Management

Following consultation with our advisory medical board, the following recommendations are provided:

• Do not implant unused affected devices.
• Monitor patients according to standard practice.
• Preventive replacement of the device is NOT recommended, as complications from replacement occur more frequently than the harm from premature battery discharge due to short circuits caused by lithium clusters (refer to the appendix for selected references).
• In the event of an ERI in these devices, immediate replacement is recommended. Currently, there is no factor, method, or test to identify if a device is approaching ERI due to premature discharge or to accurately predict the remaining battery life after ERI.
• Physicians should reconfirm the use of remote monitoring to minimize periods without bradycardia and tachycardia therapy.
• Register patients on the Merlin.net site, which uses "direct alerts" to immediately notify you of ERI. Remind patients already registered on Merlin.net about the importance of using remote monitoring.
• Review the printout of the most recent programmed parameters (provided as an example).
• Ensure that the "Alarm Triggering Upon" setting is configured to "Device Reaches Elective Replacement Indicator (ERI)" for both "View on FastPath" and "Notify Patient" options.
• If the "Device Reaches Elective Replacement Indicator (ERI)" alarm is disabled, it is recommended to meet with the patient as soon as possible to enable this parameter.
• Inform patients that upon activation of the ERI, they will feel a vibration alert. At the next scheduled visit:
• Interrogate the patient's device to determine if the ERI has been triggered.
• Conduct a patient test to ensure the patient can feel and recognize the vibration alert. Patients who do not feel the vibration alert may experience device or battery failure without their knowledge.
• Instruct the patient to contact you immediately if they feel a vibration alert.
• An outpatient assessment should be conducted to determine the cause of the alert, as other non-critical events can also trigger a vibration alert.

St. Jude Medical understands that some patients may require a unique clinical approach. If a decision is made to replace an affected device due to individual patient circumstances, St. Jude Medical will provide a free device replacement. Please return all explanted devices to the CDM for further evaluation.

For any questions regarding patient management, including observed changes in battery life, please contact your local sales representative or St. Jude Medical Technical Support at +46-8474-4147, available 24 hours a day, 7 days a week.

Your St. Jude Medical representative will replace any affected product in your center(s). To determine if your device's serial number is affected by this advisory, please visit: www.sjm.com/batteryadvisory

We apologize for any inconvenience this may cause you and your patients.

Sincerely,

/signed/

Jeff Fecho

Vice President, Global Quality

Attachments

Appendix: Models by Country Outside the USA

Table 2: Frequency of Premature Battery Discharge

The table below presents data on affected devices collected worldwide based on the analysis of devices returned due to premature battery discharge. Among the 841 devices, 46 batteries showed confirmed short-circuiting due to lithium clusters that formed a bridge between the battery's cathode and anode. In the remaining 795 devices, short-circuiting was not confirmed during analysis of returned products, but lithium clusters were noted during battery analysis, and no other causes for premature battery discharge were identified. Therefore, the table below includes both confirmed and unconfirmed cases of short-circuiting to help you assess the risk for your patients:

Publications on Complications Related to Device Replacement

1. John W. Moore III, William Barrington, et. al.; "Complications of replacing implantable devices in response to advisories: A single center experience"; International Journal of Cardiology 134 (2009) 42-46 (5.5% overall, 2.1% serious complications)
2. Paul A. Gould, MBBS, PhD, Lorne J. Gula, MD, et. al.; "Outcome of advisory implantable cardioverter-defibrillator replacement: One-year follow-up"; Heart Rhythm, Vol 5, No 12, December 2008 (9.1% overall, 5.9% serious complications, including two deaths)
3. Krystina B. Lewis, Dawn Stacey, R.N., Ph.D, et. al.; "Estimating the Risks and Benefits of Implantable Cardioverter Defibrillator Generator Replacement: A Systematic Review; PACE, Vol. 39, July 2016 (7.5% overall, 4.0% serious complications)