Medtronic Inc. announced Thursday that the U.S. Food and Drug Administration has approved broader use of its lead alert software that will ultimately ensure that a variety of leads, not just its own, are working properly.

The product, called Lead Integrity Alert (LIA), has been a standard feature on Medtronic devices since 2008. But given that pacemaker and defibrillator leads — the wires that connect devices to the heart — are considered the weak link in the cardiac rhythm therapy chain, the company believes the technology is an important safety feature to spot problems with non-Medtronic leads.

"We've seen the effectiveness of the LIA software with Medtronic devices and leads these past four years, and we know it can have an impact beyond our leads," said Dr. Marshall Stanton, vice president and general manager of the tachycardia business at Fridley-based Medtronic.

The software can now be used to detect performance issues on leads made by other companies — such as Durata and Riata defibrillator leads made by St. Jude Medical Inc. and Endotak defibrillator leads made by Boston Scientific. Those leads must be connected to a Medtronic device.

Medtronic said its software has been shown to detect lead issues in non-Medtronic leads at a greater rate than standard impedance monitoring alone. Impedance monitoring measures the electrical continuity of a lead four times per day.

For Durata and Riata leads, Medtronic said its software detected issues six times more frequently than impedance monitoring. For Endotak, circuit issues were detected four times more frequently, Medtronic said.

St. Jude's technology

Officials at St. Jude said Thursday that they, too, have developed lead monitoring that goes beyond impedance testing to ensure leads deliver therapy when needed. One system of algorithms, SecureSense, withholds inappropriate shock therapy if the lead has failed. Another, DynamicTx, can automatically adjust shock configurations if an electrical short occurs.

"St. Jude Medical believes that lead monitoring algorithms are an important safety feature that help ensure successful delivery of high-voltage therapy," spokeswoman Amy Jo Meyer said. "We have continued to prioritize the development of innovative technologies that enhance patient safety, as evidenced by multiple advanced lead detection algorithms contained in our devices."

Dr. Kenneth Stein, chief medical officer for Boston Scientific's cardiac rhythm management business, said Medtronic's study of its software showed "that the Boston Scientific Endotak lead family had the fewest number of failures and lowest rate of failures compared to the competitive leads in the study. These data further add to the wealth of clinical evidence demonstrating that Boston Scientific has designed the most reliable ICD leads in the industry."

Medtronic officials said Thursday that FDA approval will give patients with other companies' leads another layer of protection against possible problems. According to Medtronic, there are about 12,000 Medtronic LIA-enabled defibrillators connected to non-Medtronic leads. That includes nearly 5,100 Endotak leads and 6,100 Riata and Durata leads. Nearly 500 leads attached to Medtronic devices come from other manufacturers. Medtronic said an external panel of physicians adjudicated non-Medtronic lead issues that were identified by its software.

Stanton said Medtronic is the only company that has labeling from the FDA that says their algorithm works with other leads.

Sensing trouble

Leads not only deliver life-saving therapy to the heart when needed, but they enable the device to sense when the heart is in trouble. But the thin wires can fracture, disconnect from the heart and short-circuit — raising concerns about patients receiving unnecessary shocks or, worse, not getting a shock when needed.

Most device makers have experienced lead problems over the years. In fact, Medtronic developed the software after problems with its Sprint Fidelis lead. St. Jude's Riata lead was removed from the market in late 2010 after it was discovered that the lead's inner wires were coming through its outer insulation. A year later, the FDA recalled the device. St. Jude Medical has repeatedly said it has not seen similar problems with its Durata leads, pointing to years of data from monitoring of thousands of patients.

Dr. Robert Hauser, a cardiologist with the Minneapolis Heart Institute who has highlighted lead safety concerns over the years, said the news of FDA approval is good. "We have found the LIA to be a very effective tool for preventing inappropriate shocks due to lead fractures," he said. "Now we can use it for other manufacturers' leads."

Stanton said that there are thousands of patients with leads that have been recalled or are under a safety watch. Gaining FDA approval to market its software to detect problems could draw more patients to Medtronic, he said."Clearly, patients who have those can benefit from this algorithm."