A cardiologist with offices in New York City and New Jersey carried out what federal authorities say is the largest health-care fraud ever recorded by a single practitioner in those states.

Prosecutors said José Katz, 68, of Closter, NJ, pleaded guilty yesterday in Newark federal court to submitting $19 million in fraudulent billings to Medicare, Medicaid and private insurers.

The feds said he subjected thousands of patients to unnecessary and potentially life-threatening treatments as a result of phony diagnoses.

He also admitted keeping his wife on his payroll, even though she did little or no work, so she would be eligible for a quarter-million dollars in Social Security.

He’ll be sentenced on July 23 for conspiracy to commit health-care and Social Security fraud.