Matthew Perrone, AP

The Food and Drug Administration issued a warning letter to medical device maker St. Jude Medical, Inc. due to the company promoting its device for an unapproved use. In a letter dated April 23, the FDA takes issue with claims on a St. Jude website promoting its Epicor ablation system. The device is approved to eliminate diseased heart tissue during surgery using intense ultrasound energy.

The FDA has granted the company permission to study the device for a new use in treating atrial fibrillation, which causes the upper chambers of the heart to contract irregularly, potentially causing stroke. But the FDA says St. Jude's site is already promoting the system for that use by touting its effectiveness against atrial fibrillation.

“As a result, you are in violation of FDA's prohibition against promoting before FDA has approved the device for commercial distribution,” states the warning letter. “The company is working diligently to address the points raised in the warning letter and to resolve the FDA's concerns,” said St. Jude spokeswoman Marisa Bluestone, in a statement.

FDA uncovered the violation during a routine inspection at St. Jude's facility in July. FDA inspectors also uncovered brochures and marketing materials promoting the system for non-FDA approved uses. The letter addressed to Jane Song, president of St. Jude's Atrial Fibrillation Division, requests the company immediately stop using the promotional materials. The agency gave St. Jude 15 business days to correct the problems and provide a plan to prevent future violations.

St. Jude is one of several device makers working to win approval to market a device to treat atrial fibrillation. About 2.2 million adults in the U.S. have the condition, which accounts for about 15 percent of strokes, according to the American Heart Association. The condition is usually treated with blood thinning drugs, and occasionally, open heart surgery.

Last year rival device maker Johnson & Johnson became the first company to win FDA approval for such a catheter to treat atrial fibrillation.

The FDA regularly issues warning letters to companies that do not follow regulations for manufacturing and marketing. The letters are not legally binding, but the agency can take companies to court if they are ignored.