St. Jude Medical Inc., a leading medical devices manufacturer, has stopped marketing two of its cardiac defibrillator leads after incidents of them malfunctioning were reported.
Business Week reports St. Jude has stopped sales of its QuickSite and QuickFlex wires due to exposed conductive ends that could present problems to patients who rely on these wires to regulate their heart rhythm. Like problems with other defibrillator leads it markets, the conductive ends on the QuickSite and QuickFlex can break through the silicone insulation.
The company indicates about 171,000 QuickSite and QuickFlex leads have been implanted in patients. The conductive ends break through the silicone insulation in about 3 to 4 percent of the patients who’ve had them implanted. St. Jude acknowledges it has received 39 reports of this error happening but it has not caused any injuries or device malfunctions. This, the company suggests, may be a lower figure than the actual amount of leads that have broken free of the insulation because it has not resulted in any injuries.
The QuickSite and QuickFlex leads attach to resynchronization devices to regulate heart rhythm. According to the report at BusinessWeek.com, problems with “externalized conductors were found on the silicone end of wires.” These leads attach to the heart’s lower left chamber and regulate the beating on each side of the organ.
St. Jude’s announcement covers QuickSite and QuickFlex leads sold before 2008. After that date, the leads were covered in a “hybrid” insulation that’s purportedly not prone to the same errors.
This is the second announcement regarding St. Jude defibrillator leads it manufactures or has since recalled due to similar problems with far more serious consequences. A recently published analysis of the Riata line of leds indicated in the last week they were the cause of death in at least 20 patients.
The company stopped selling those leads in December 2010 but not until it had sold nearly 227,000 of them. Still, more than 79,000 people in the U.S. and more than 49,000 others around the world are relying on Riata or Riata ST leads to deliver life-saving shocks to their heart. They were eventually recalled a year after the company stopped selling them and the Food and Drug Administration declared it a Class I recall, meaning use of these leads put a patient at serious risk of injury or death.
When it short-circuits, the Riata leads may deliver unnecessary shocks to the heart or may not work when needed. Each scenario poses life-threatening risks to a patient and could happen at any moment, essentially.
Similar to the QuickSite and QuickFlex leads, exposed conductive ends which couldn’t be contained by the wires’ silicone insulation resulted in short circuiting. The risks posed by the leads in the most recent announcement do not appear to be as severe as those from the Riata line.