Implantable Heart Defibrillators Ineffective, Says Two Studies
November 7th, 2007 amy
Implantable heart defibrillators took a beating Tuesday when researchers reported poor results of two studies, which were funded by St. Jude Medical, at the annual conference of the American Heart Association. The implantable defibrillator market has declined in the past few years, but these studies didn’t produce the good news the market needs.
Both studies focused on a type of implant called cardiac resynchronization therapy. The implants, which work like pacemakers, can shock the heart back into action when it stops beating.
The first study, which consisted of two groups of about 85 patients each, failed to improve the ability to exercise for a specific population of heart failure patients. These patients met a specific type of measurement of electrical stimulation in the heart called QRS, and their heart-walls don’t contract efficiently. No statistical difference between the two groups was found.
The second study, which focused on two groups of 197 heart failure patients, showed that the resynchronization implants failed to prevent the most severe, or “permanent,” type of atrial fibrillation, which is an abnormal heart rhythm. Results showed the instances of permanent atrial fibrillation were identical in both groups. He said they were also very low, at 3.3 percent. St. Jude spokesperson said the study will be followed for another year.
These study results were only minor hits to the defibrillator market compared to other major setbacks in the past few years. In mid-October, Medtronic ceased production of the Sprint Fidelis lead, a wire connecting the defibrillator to the heart, after the product was linked to five deaths. In June 2005, St Jude announced that some of its implantable St Jude defibrillator models have a software problem that could cause the heart-shocking device to malfunction.
