St. Jude warns batteries in up to 350000 defibrillators worldwide could short circuit and fail - Minneapolis Star Tribune

St. Jude Medical, the Minnesota-based maker of heart devices, announced Tuesday that nearly 350,000 defibrillators implanted in patients may be prone to short-circuiting in a way that causes the device to fail unexpectedly. Two deaths have been associated with the devices failing.

“While it is a rare occurrence (0.21 percent), we want to ensure we are providing the information physicians need to best care for their patients,” a St. Jude spokeswoman said in an e-mail Tuesday morning. “We have asked physicians to contact their patients with information about this advisory. Device replacement is not recommended unless the physician determines otherwise.”

Just hours before a Food and Drug Administration alert on the failures was published Tuesday morning, St. Jude announced that it detected the potential for premature battery depletion in several models of implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy defibrillators (CRT-Ds). The at-risk models include: Fortify, Fortify Assura, Quadra Assura, Quadra Assura MP, Unify, Unify Assura, and the Unify Quadra. The action does not affect any models of pacemakers.

St. Jude said the problem with the defibrillators is in the lithium batteries.

During charging, the lithium material can form “clusters” inside the device that may cause a short circuit and lead to battery depletion, depending on the location of the cluster. The company found that battery depletion can happen within a day to a few weeks, if a short circuit occurs.

So far, 841 of the 398,740 devices distributed worldwide have been confirmed to have premature battery depletion “in association with” lithium cluster formation, including 549 in the U.S. Forty-six of the devices had visible electrical shorting from the clusters.

Roughly 349,850 of the devices remain implanted in patients worldwide today and are at risk. At this point, “prophylactic” replacements are not being recommended, as the risks of complications from replacement surgery are thought to be greater than the risk of premature battery failure.

But devices should be checked and replaced immediately if a battery warning is detected. Such an alert is supposed to trigger a vibratory alert in the device that the patient can feel. Based on the circumstances, St. Jude may cover the cost of a replacement device, if one is needed.

St Jude stock dropped more than 3 percent in morning trading, to $78.57. The $22.4 billion medical device company, based in Little Canada, is in the process of being acquired by Abbott Laboratories in suburban Chicago.

An Abbott spokesman declined to say when Abbott became aware of the widespread battery issues, but it still expects to close its $25 billion acquisition of St. Jude by the end of the year.

The defibrillator battery warning is the second major hit to St. Jude devices in just over a month.

In late August, short-selling firm Muddy Waters Capital announced what it said were major cybervulnerabilities in St. Jude pacemakers and other implanted devices. St. Jude has since filed a defamation lawsuit and called the allegations false.

Despite an initial dip in St. Jude’s stock price, market analysts and independent cybersecurity researchers have said Muddy Waters’ fears may be overblown. The FDA has not recommended taking any action with regard to the cybersecurity allegations.