July 17, 2012 — The initial findings from a study suggest that large-diameter Riata defibrillator leads are more likely to erode than small-diameter leads, according to St. Jude Medical Inc. The company voluntarily stopped selling the large-diameter leads in December 2010, and one year later, the U.S. Food and Drug Administration (FDA) issued a Class I recall of the product.
The study found that 24% of large-diameter Riata 8F leads developed inside-out erosion, compared with just 9.3% of the smaller-diameter Riata ST 7F leads. The study involved 724 patients in 20 locations in the United States, Canada, and Japan. All of the patients had the Riata or Riata ST silicone defibrillation leads. The company will continue conducting the study to better understand the long-term performance of the devices over the next two years. No patient recommendations have been made at this time.
The problem with erosion is that the devices can prematurely wear out the silicone insulation around the defibrillator leads (the long wire that delivers an electrical shock to the heart). Without the silicone insulation, the device can malfunction, and may fail to deliver a life-saving shock in the event of an emergency.
The leads connect heart tissue and a cardiac defibrillator, which helps the heart pace its beats and provides a high-voltage electrical shock when the heart has a severe irregular rhythm.
St. Jude is seeking the retraction of two journal articles linking the Riata defibrillators to a higher risk of death. The Heart Rhythm Journal published a study linking the Riata defibrillators to at least 20 deaths. St. Jude said that the facts in this study were inaccurate and biased. The study also compared the performance of the St. Jude Riata defibrillator to the Medtronic Quattro Secure, and found a 9-fold increased risk of death associated with the St. Jude devices.
The St. Jude Riata defibrillator has also been linked to a risk of perforation, which could cause cadiac tamponade. This condition occurs when the heart bleeds into the heart sac, which increases pressure around the heart and prevents the heart from beating effectively. This condition can be lethal.
Approximately 80,000 people were implanted with the Riata devices. St. Jude is the second-largest maker of defibrillators in the U.S.