Study Examines Deaths Caused by Defibrillator Leads A new study published by the Heart Rhythm Jour

Study Examines Deaths Caused by Defibrillator Leads
A new study published by the Heart Rhythm Journal examines the details behind last year’s recall of leads used with St. Jude Medical’s Riata and Riata ST implantable cardioverter defibrillators.

Resurfacing the issue, the study found that the faulty wires directly caused 22 deaths. There were a total of 133 deaths—22 caused by Riata or Riata ST lead failures, five caused by Quattro Secure Lead failures (manufactured by Medtronic Inc.), and the rest caused by unspecified factors.

The U.S. Food and Drug Administration’s (FDA) recall on Dec. 21 was prompted by exposed wires from the protective lead casings. The study, however, shows that short-circuits between high voltage components rather than externalized conductors were the typical cause of death in the 22 fatalities associated with Riata. Author of the study, Robert Hauser, M.D., told The New York Times, “When I went in, I thought I would find more deaths related to externalized cables. But as it turned out, the externalized cables really didn’t factor in.”

There is some dissent from the St. Paul, Minn.-based company. St. Jude’s Chief Medical Officer Mark Carlson, M.D., claims that Hauser’s study contains errors, namely that two of the deaths had been counted twice, bringing the count to 20 rather than 22. Hauser’s peer-reviewed study gained their numbers from searching the FDA’s Manufacturer and User Device Facility Device Experience database, which aggregates reports of “adverse events involving medical devices.”

Riata and Riata ST leads had been on the market since 2000 and 2005 respectively, and in that time were estimated to have been implanted in a total of 128,000 patients worldwide. Patients who have these leads implanted with their defibrillator are at risk for short-circuits—but removing the wires is not recommended as that, too, is considered high-risk. Hauser recommends that physicians pay attention “to what are the electrical signs that might help … identify patients who are at risk” for lead shorts.