A New York City cardiologist with offices on Fifth Avenue and in New Jersey admits he intentionally misdiagnosed up to 80 percent of his patients with heart problems so he could collect millions in extra Medicare money.

Dr. Jose Katz, 68, pleaded guilty to falsifying charts diagnosing patients with angina and other heart ailments so he could prescribe extra tests and treatments when hundreds of patients did not need them.

Prosecutors said it was the largest fraud ever executed by a single doctor in New York or New Jersey.

"After years of prominence in his field, Jose Katz will now be remembered for his record-setting fraud," said U.S. Attorney Paul Fishman.

In court Wednesday he agreed his actions could have caused "serious bodily harm" to his patients. He and his lawyer disagreed when prosecutors said some patients were at risk of death due to his actions.

In all, Katz admitted his scheme took in over $19 million.

Katz's crimes went on from at least 2004 through 2012. His resume said he is affiliated with NewYork-Presbyterian Hospital, but a spokeswoman said he has not been linked there since 2003.

Fishman said many patients who were exploited went to Katz's clinics, called Cardio-Med Services in Union City, Paterson and West New York. He also ran clinics called Comprehensive Healthcare in Manhattan and Queens.

Katz said he performed many so-called EECP procedures based on false diagnoses to overbill Medicare and private insurers like Blue Cross and Aetna.

In court, Katz told the judge as a doctor he had "done everything he could to help patients." The judge told him he would have time to speak at sentencing set for July 23. After the court hearing, Katz and his attorney, Blair Zwillman, left the courthouse admitting mistakes were made but insisting Katz always cared for his patients.

Katz faces up to 10 years in prison on the conspiracy to commit health care fraud charges. He also admitted creating a no-show job in his office in order to rip off more than $250,000 in Social Security benefits.

Katz was born in Cuba but is a U.S. citizen. Prosecutors said he spent $6 million advertising on Spanish-language television and radio to try to lure in patients.

Fishman said investigators are attempting to contact all the patients affected by the fraud, who can also reach out to the New Jersey FBI or U.S. attorney's offices for additional information.