Thoratec Corp. issued a voluntary Urgent Medical Device Correction Letter to all hospitals who have patients supported with the HeartMate II LVAS reminding them to monitor the expiration date of the backup battery contained within the HeartMate II "Pocket" System Controller, as specified in the product Instructions for Use. This backup battery has a 36-month expiration date. If allowed to expire, an advisory alarm, indicated by a yellow wrench symbol, is triggered. This alarm occurs at 12:00 a.m. on the first day of the month in which the backup battery expires.
