In December, when the U.S. Food and Drug Administration recalled St. Jude Medical's Riata defibrillator lead over potential risks of injury or death, it left about 76,000 U.S. patients facing a serious question: What do I do now?

The Riata leads were pulled off the market because wires have broken free from the outer insulation in some of the devices, which shock the heart when they sense an irregular heartbeat. The discovery raised fears that damaged wires might not deliver lifesaving treatment when needed -- or deliver an unnecessary jolt.

But there seems little consensus on the next step for those who have the Riata leads connected to their hearts. Unlike a defective toaster or recalled automobile, implanted medical devices aren't easy to take back.

The issue has spurred intense debate among physicians and plenty of anxiety among patients. St. Jude Medical is conducting an evaluation study of at least 500 patients in the United States, Canada and Japan and has recommended that doctors monitor their Riata patients.

"We need more data and more information to inform decisionmaking," said Dr. Mark Carlson, medical director and senior vice president at St. Jude.

That seems to be about the only thing on which all parties agree -- the need for more information.

"Now that it's recalled, we don't have the data we need to manage it," said Dr. Robert Hauser, a cardiologist at Abbott Northwestern Hospital in Minneapolis who conducted a "Riata Summit" on Jan. 20. "We are ill-prepared to counsel our patients because we do not have the clinical evidence to support any recommendations."

In 2010, St. Jude sent a letter to doctors, alerting them to a problem with Riata and Riata ST leads, wires that run from a defibrillator to the heart.

Doctors discovered that, with the Riata, small inner wires were coming through the lead's outer coating. At the time, St. Jude said the rate of abrasion was 0.47 percent nine years after the original implant, with 0.047 percent demonstrating "externalized cables."

The Little Canada-based company removed Riata leads from the market in December 2010, after selling about 227,000 worldwide.

Then, late last year, St. Jude sent another letter out, upping the abrasion rate to 0.63 percent. In addition, a study of 212 patients in Ireland who received St. Jude's Riata defibrillator lead was even more problematic. It found that 15 percent had suffered such an "insulation breach," which could interfere with the device's lifesaving therapy. In addition, normal screening of the device or even X-rays might not pick up the breach, and patients would have no outward clue that their lead wire might be compromised.

The FDA issued its recall shortly after that.

St. Jude has recommended that doctors continue monitoring their patients' implanted defibrillator systems and use X-rays or fluoroscopy if there is evidence of a lead electrical failure.

Seeking a solution

Hauser, a senior consulting cardiologist with the Minneapolis Heart Institute Foundation who is internationally known for researching defibrillator failures, and Dr. David Hayes of the Mayo Clinic organized the Riata Summit to try to find consensus about what should be done for Riata patients.

The main lesson? "We walked out of there knowing that monitoring these patients would be a challenge," Hauser said.

Many physicians who attended the summit recommended fluoroscopic screening of patients with the lead, Hauser said. Dr. Christopher Ellis of Vanderbilt University recommended the scans, which he said do a better job uncovering the problem. At Vanderbilt, he said, fluoroscopic exams showed that 26 percent of patients who'd had their Riata leads for at least five years showed externalized wires.

"Watching some of them, I'm not so sure it won't just unzip over time," he said of the wires.

But Hayes said it is not clear if fluoroscopy would do anything but rattle the patient. Just because the inner wires have come through the outer insulation doesn't mean the device won't work properly. "There is a tendency to overreact," Hayes said. "If there is a real problem with a patient, you need to deal with that individual patient and act."

Carlson, of St. Jude, told physicians at the summit that there have been no reports of the device failing to pace or deliver a shock that are attributable to externalized wires. "The appearance of an externalized conductor alone should not provoke an overreaction," he said.

Patients -- and their doctors -- are left with three options: Leave the lead connected to the defibrillator and monitor for signs of trouble; disconnect the lead and leave it in place while inserting new wires alongside it. Or take out the whole thing and replace it.

But surgery to remove leads in the body can be difficult -- and dangerous -- since scar tissue can form over the cable. Lead removal can damage the heart itself.

"It's a high-risk proposition, and that's why we don't want to overreact," Hayes said.

Dr. Samir Saba, director of cardiac electrophysiology at the University of Pittsburgh Medical Center, said: "There is a risk for leaving it in there -- and there is a risk for an invasive procedure to take it out. Where is the break-even point for these risks?"

At Pittsburgh, he said, physicians have intensified their monitoring of Riata patients -- increasing in-person visits to once every three months and upping remote monitoring to once a month.

But, in the end, he said what a patient with Riata decides to do comes down to several factors: How old is the patient, how long has the Riata lead been in place and how much risk are they willing to accept?

'I wanted it out'

Dan Meyer of Fridley admits he is one of those patients whom doctors call "high-anxiety." One day, his wife, Kristina, was reading the paper when she read about the Riata recall. "I went, 'Oh!'" Kristina Meyer said.

A visit to his doctor confirmed that the defibrillator Dan Meyer had implanted seven years ago was connected to his heart by Riata leads, Meyer said. It also confirmed that the leads were bad. Meyer, who looks much younger than his 47 years but can no longer work because of his heart disease, made a quick decision.

"I wanted it out," he said.

But his doctor pointed out that extracting the wire carried its own dangers. Meyer's heart is enlarged, the result of its working hard to make up for a missing artery. And the device had been in place a long time.

"He said it could leave a hole in my heart," Meyer said.

So, instead, he decided to disconnect the Riata leads and go with a new defibrillator with new wires running alongside.

"They said 'You can monitor it,'" Meyer said. "But I've been shocked before. I didn't want it to shock me when I was picking up my daughter."

Now, he said, "I feel good. I know that, all of a sudden, it's not just going to shock me for no reason."

James Walsh • 612-673-7428