St. Jude Warns about Surgery with Older Pacemakers

It seems that St. Jude Medical has a bit of a problem with some of its older pacemakers.

On January 29, the company issued a “Dear Colleague” letter advising physicians that some of their older pacemaker models (Affinity, Entity, Frontier, Identity, Integrity, Sustain, Victory, and Zephyr) can drop their output voltage during surgical electrocautery procedures, which involve electrically generated heat. This drop of the output voltage can mean that the pacemaker effectively ceases to function.

This is rather unusual. At one time, the opposite effect was more common. Although newer pacemaker models are designed to allow for pacemaker management during surgery, back in the 1990s the problem of out-of-control pacemakers was sufficiently common that it was named Runaway Pacemaker Syndrome.

In 2011, the Heart Rhythm Society (HRS) and the American Society of Anesthesiologists (ASA) published the “HRS/ASAExpert Consensus Statement on the Perioperative Management of Patients with Implantable Defibrillators, Pacemakers, and Arrhythmia Monitors: Facilities and Patient Management.” While not having the status of a regulation, this guideline has nevertheless become something of a de facto standard.

According to these guidelines, placing a magnet over the pacemaker should cause it to pace at the programmed output voltage at a default “magnet rate” pace. However, the St. Jude letter says, "Placing a magnet over the device or programming to an asynchronous pacing mode will not prevent this temporary reduction in pacing output.”

Therefore, St. Jude says, the physician should evaluate the individual patient's dependence on the pacemaker prior to any electrocautery procedure, particularly a pacemaker procedure. “If pacemaker dependency is identified, either do not use electrocautery or employ appropriate precautions to ensure that the heart rate will be supported in the presence of electrocautery. Consideration of placing a temporary transvenous pacemaker is appropriate.”

Although this letter is now posted on St. Jude Medical's professional website, Westby G. Fisher, MD, wrote onMedCityNews, “...it is concerning that such an unusual (and potentially fatal) failure mode of these older models of pacemakers has not been made more public to patients with these older St. Jude pacemakers so they can serve as their own advocates when surgery is in its planning stages.”