ANZCDACC Advisory Notice 22nd December 2014
Device: All models of RF enabled St. Jude Medical Implantable Cardioverter Defibrillators (Ellipse Fortify Assura, Unify Assura, and Quadra Assura) and Pacemakers (Assurity and Allure) when used with Merlin@home RF Remote Monitor Model EX1150.
Advisory Grade TGA: Hazard Alert
ANZDACC Advisory Grade: Elective/Routine
Number in Australia: Not known or identifiable
Risk: All currently implanted devices matching the above models have the potential for reversion to backup operation mode with programming adjustments automatically made to Bradycardia and Tachycardia parameters. High voltage devices maybe susceptible to inappropriate therapy due to reset of programming to back up operation mode.
Description: St Jude Medical has advised there is a potential for the aforementioned devices to be placed into backup operation mode when wirelessly remote monitored with St Jude Merlin@Home units. The anomaly exists at rates of 0.25% in High Voltage devices based on 55,000 devices and 0.016% for the Low Voltage range (12,000 devices). The root cause is due to a timeout occurring when marginal telemetry between the implanted device and bedside transmitter is present causing a software reset. Back up operation mode default programming is VVI 67bpm with 5.0V @ 0.6ms and VF zone only @ 146bpm/410ms with Max outputs shocks >36J. In HV devices bipolar pacing continues, if previously programmed, but in LV devices pacing polarity reverts to unipolar.
Inductive remote monitored or non remote monitored devices are not affected.
Presentation: Patients device will alert via an audible beeping tone or vibration and Merlin.net will receive an alert transmission via Merlin@Home transmitter.
Advice: No change to device follow up schedule (remote or in clinic) is advised until the issue presents.
Patients that are affected by this issue require immediate in person follow up to allow for software rebuild and device reprogramming.
A software upgrade for the Merlin@home transmitters will be performed automatically to correct the anomaly in late January 2015.