St. Jude's new generation of defibrillators

St. Jude Medical Inc. said Tuesday that the U.S. Food and Drug Administration has approved a new defibrillator that the company says helps prevent unnecessary shocks to the heart.

For the past two years, Little Canada-based St. Jude has been fighting problems with its now-recalled Riata defibrillator leads -- including concerns that the wire that connects the device to the heart could prevent the defibrillator from delivering lifesaving therapy or, instead, give an unneeded and painful jolt.

St. Jude's new Assura implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy defibrillators (CRT-Ds) feature a new algorithm designed to decrease inappropriate shocks for patients. An ICD is an implantable device that treats potentially lethal, abnormally fast heart rhythms, which often lead to sudden cardiac death.

A CRT-D device resynchronizes the beating of the heart's lower chambers, which often beat out of sync in heart-failure patients.

In announcing the commercial availability of the new defibrillator, St. Jude officials touted new technology that can tell the difference between "noise" from a faulty wire and an actual heart problem.

Assura, however, is not a specific response to Riata. St. Jude began developing its new technology several years ago, said Dr. Mark Carlson, chief medical officer and a senior vice president for St. Jude's cardiac rhythm management division.

The new algorithm is expected to give doctors advance warning of lead-related complications and can automatically withhold therapy. St. Jude says the technology can tell the difference between lead noise and true problems that would trigger the defibrillator's therapy.

"For some patients, the fear of receiving a shock can either prevent them from receiving a potentially lifesaving device, or cause anxiety that reduces their quality of life once they receive the device," said Dr. Eric Fain, president of St. Jude Medical's cardiac rhythm management division. "These devices directly address this patient concern and provides physicians additional tools to manage individual patient needs."

St. Jude took Riata defibrillator leads off the market in December 2010 after studies found that some of the device's wires protruded from the lead's silicone insulation.

The FDA issued a recall of the device in December after St. Jude discovered such protrusion was more common than previously thought.

In a March article in Heart Rhythm Journal, Minneapolis cardiologist Dr. Robert Hauser connected St. Jude's Riata defibrillator lead to at least 20 patient deaths -- not because of the protruding wires but because of the leads short-circuiting.

St. Jude has disputed Hauser's findings and unsuccessfully sought to have the article retracted.

"I bet they have been working on this for more than a year," he said in an e-mail.

Thom Gunderson, an analyst with Piper Jaffray & Co., said the issues addressed by Assura are "universal," rather than being a response to the Riata problems.

"Companies are constantly striving to improve lead performance, as well as other important features like fewer unnecessary shocks," he said.