The U.S. Department of Justice and Federal Bureau of Investigation (FBI) are investigating whether two California doctors conducted hundreds of unnecessary heart procedures in an effort to swindle the federal Medicare program. Last week, dozens of FBI agents raided the Redding Medical Center, owned by Tenet Healthcare Inc., to obtain records of heart surgeries performed by the physicians, identified as Dr. Chae Hyun Moon and Dr. Fidel Realyvasquez.

According to an FBI affidavit filed last week, medical officials, including several employed by the Redding hospital, recently raised questions about the high number of heart surgeries performed at the facility. The affidavit indicates that 25 to 50 percent of patients at the hospital may have undergone unnecessary invasive coronary procedures, including angioplasties, heart valve replacements, coronary bypasses and heart catheterizations. Over 160 patients who underwent heart surgeries performed by Moon and Realyvasquez between December 1998 and October 2002 have since died, although it is not clear whether these deaths were the fault of the physicians. Officials have yet to comment on whether Tenet Healthcare is a focus of the investigation as well.