"The Food and Drug Administration is investigating allegations by a former Medtronic Inc. engineer that the medical-device company didn't adequately test its new Concerto cardiac device for patients with congestive heart failure. The FDA's Minneapolis office is conducting an inquiry into the claims by Christopher Fuller, who worked as an engineer at Medtronic until late 2005. Mr. Fuller's concerns deal with one of the Minneapolis company's newest and most lucrative products. The Concerto device is one that can resynchronize the heartbeat of a patient and also provide backup "defibrillator" capability to save the patient's life if the heart goes into cardiac arrest."However, the Food and Drug Administration said it completed an investigation of Medtronic over its recently launched Concerto implantable heart devices but hasn't found anything to indicate that the devices are unsafe.