Battery Expiration in HeartMate II LVAS ‘Pocket’ System Controller Linked to 2 Patient Deaths

circulatory system blood vessels heart
circulatory system blood vessels heart
The device correction letter is intended to prevent occurrence of preventable advisory alarms that could lead patients to attempt a System Controller exchange.

Healthcare practitioners should remind patients to monitor the expiration date of the backup battery contained within the HeartMate II “Pocket” System Controller (Thoratec Corporation), the device manufacturer announced in a press release.

Since September 1, Thoratec has received multiple reports from several hospitals regarding patients who encountered an advisory alarm from their HeartMate II Left Ventricular Assist System (LVAS) due to the expiration of their System Controlled backup batteries. Some of the patients who received the advisory alarm attempted to switch from their primary to backup System Controller. The alarm resulted in 2 patient deaths and 1 serious injury among patients who were unable to connect their pump to their backup System Controller in a timely manner. Thoratec released an Urgent Medical Device Correction Letter in hopes of preventing the occurrence of “certain preventable advisory alarms that may result in patients deciding to attempt a System Controller exchange.”

The HeartMate II has a backup battery with a 36-month expiration date. The product instructions provide information on monitoring and changing the backup battery before it reaches the 36-month expiration date, thus preventing potentially harmful advisory alarms.

Patients with HeartMate II LVAS System Controller serial numbers starting with the letters “EPC” are unaffected. Patients whose System Controller serial numbers start with “PC” and who received their device more than 2 years ago should contact their doctors immediately. Physicians should check the expiration date of both the backup battery and primary battery and replace these components if necessary.

Patients who received their HeartMate II LVAS implant less than 2 years ago should ask their physicians to check both the primary and backup System Controller batteries during each clinical visit. Backup battery replacement should take place approximately 6 months before expiration.

The company urged patients who experience a Backup Battery Advisory alarm to follow all instructions listed in the product Patient Handbook and to contact their hospital for further instructions. Patients should not attempt to replace the System Controller unless instructed to do so by their hospital.

Thoratec instructed patients with questions or those who experience this issue to contact their doctor or ventricular assist device coordinator at their hospital. Clinicians with questions should contact their Thoratec representative or call Thoratec’s 24-hour HeartLine at 1-800-456-1477.


  1. Letter sent to remind hospitals to check backup battery expiration for “Pocket” System Controllers used with the HeartMate II® Left Ventricular Assist System (LVAS) [news release]. Pleasanton, CA: Thoratec Corporation; September 14, 2015. Accessed September 16, 2015.