Nine cardiologists accused of carrying out unauthorised treatments on patients were arrested by the Italian police as part of an investigation sparked by suspicious deaths in northern Italy.
The cardiologists, who all worked at some point or another for a hospital in Modena, are also accused of knowingly using defective equipment and raising money under false pretences to fund their activities.
They face charges of corruption, criminal association, embezzlement, fraud and carrying out illegal treatments, police said in a statement.
Investigators "uncovered a well-oiled organisation made up of cardiologists and representatives from companies supplying medical equipment, implicated in corrupt business affairs," the statement said.
A total of 67 people are under investigation and police have seized around one million euros ($1.2 million) from bank accounts belonging to the suspects.
The investigation "reveals -- if the serious accusations are confirmed -- that a number of professionals are sadly not playing by the rules," Health Minister Renato Balduzzi said.
Twelve companies specialising in cardiological equipment, six of which are based outside Italy, have also been banned from undertaking contracts with the national health service.
The inquiry, which covers the period of 2009 to 2011, was launched after consumer groups raised the alarm over the suspicious deaths of two patients.
One of the cardiologists was jailed while the other eight were placed under house arrest.