Tokyo ? A doctor at Saitama Medical School announced Saturday that a 61-year-old heart attack patient had been successfully treated using bone marrow cells.

Dr. Shunei Kyo said at a press conference that the patient was discharged by the hospital after being disconnected from an artificial heart.

This could be the first case worldwide in which a patient has recovered sufficient heart function to survive without an artificial heart, according to Kyo.

The patient had a heart attack on Feb. 3 and was admitted to the Saitama Medical Center in Kawagoe, Saitama Prefecture, which is operated by Saitama Medical School in Moroyamamachi.

He was fitted with an external artificial heart, but because of his age and other factors, was judged by doctors to be unsuitable for heart transplant.

On May 18, a group of doctors led by Kyo and Dr. Satoshi Gojo, a lecturer at the medical school, conducted regenerative stem cell treatment from the patient’s bone marrow. The patient’s heart function recovered to the extent that he could live without the artificial heart. The artificial heart was removed on June 30.

Kyo said doctors were unsure why the patient’s heart function had recovered to that extent.