WASHINGTON -- Implantable defibrillators are becoming less likely to malfunction but they're tougher to remove and replace than experts thought, separate studies say.
The malfunction rate fell in 2003 and 2004, said a study that expanded upon research released in September. It ran through 2002. A second study said about 8 percent of those whose devices were replaced had medical complications, some fatal, at almost twice the rate estimated by Medtronic Inc., the world's largest maker of defibrillators.
The $10 billion-a-year cardiac rhythm management industry, which includes Medtronic, Boston Scientific Corp., and St. Jude Medical Inc., was battered by recalls in 2005. From 1998 to 2001, the malfunction rate rose sharply before falling in 2003 and 2004, said William Maisel, a Harvard University researcher. The findings were based on data drawn from databases for 16,444 patients.
The complications survey, led by Andrew D. Krahn of London Health Sciences Center in Ontario, backs the stance of device makers that removing a defibrillator after a recall may be riskier than leaving it. He found that doctors removed 18 percent of 2,915 recalled defibrillators from patients from October 2004 to October 2005; 8.1 percent developed complications.