Interventional cardiology

TGA issues warning over implanted heart defibrillators

The TGA is warning cardiologists about a battery defect affecting more than 300,000 implanted heart defibrillators worldwide that could cause them to stop working earlier than expected and without warning.

A hazard alert issued by the regulatory body late yesterday, said two patients overseas died after batteries in their defibrillators depleted prematurely causing loss of defibrillation therapy.

Meanwhile 10 overseas patients have reported fainting from devices that didn’t provide pacing because of battery depletion.

The warning relates to various models of implantable cardioverter defibrillators (ICDs) and cardiac resynchronisation therapy defibrillators (CRT-Ds) manufactured by St Jude’s Medical before May 23 2015, the TGA said in its statement.

The TGA and St Jude’s Medical have issued a recall of all unused stock affected by the defect.

According to St Jude’s Medical International, the device should alert patients that batteries are running low by vibrating. When the devices are functioning normally, patients have three months to replace them after receiving the alert.

But the devices involved in the recall could stop working within 24 hours to a few weeks of patients receiving the alert, the TGA said.

The malfunction occurs when deposits of lithium form within the devices’ batteries and create abnormal electrical connections, leading to battery failure.

The TGA is warning cardiologists and surgeons not to implant unused stock of potentially affected devices.

In a letter posted on its international website and sent to doctors of patients who may be affected, St Jude’s Medical said only a small proportion of the devices had been affected.

According to the manufacturer, of 398,740 devices worldwide, 841 returned devices (0.21%) had premature depletion associated with lithium clusters

However it also said that 349,852 affected devices are still in service worldwide and, therefore, potentially at risk.

Affected models include Fortify™, Fortify Assura™, Quadra Assura™, Quadra Assura MP™, Unify™, Unify Assura™ and Unify Quadra™.

St Jude’s Medical said that while prophylactic device replacement is not recommended cardiologists should immediately change affected devices once the elective replacement indicator (ERI) is reached.

They should also perform a patient notifier test to ensure patients can feel and recognise a vibratory patient notifier alert.

“Patients who cannot feel or recognise a vibratory alert could experience battery depletion and/or loss of device function without being aware of it,” the company said.

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