David Ranta, a New York man who was wrongly jailed for 23 years, suffered a severe heart attack just one day after his release.

Ranta spent more than two decades in prison for a crime he did not commit.

The 58-year-old was freed on 21 March after being wrongly imprisoned for murder. On the night of 22 March, Ranta suffered a heart attack and was immediately rushed to a New York hospital, his lawyer Pierre Sussman told the Daily News.

"We're just trying to grasp everything that happened," Ranta's niece told the New York Daily News.

"He's great. He's doing great," she added.

Ranta's condition is stable and he is being treated in the intensive care unit, Sussman said.

"He is presently resting, with his family by his bedside," he said in a statement.

Sussman added that Ranta will remain in hospital for further treatment. He added that Ranta is thankful to all his well wishers but because of privacy concerns, his family did not want to reveal the name of the hospital.

"The accumulated trauma of being falsely convicted and incarcerated for 23 years, coupled with the intense emotions experienced surrounding his release, has had a profound impact on his health," Sussman said.

After being released, Ranta walked into the arms of his beloved family members, including some who were just children when he was incarcerated.

"Right now, I feel like I'm under water, swimming," he told reporters on the day of his release.

His sister Beverly Rivera said on Friday that Ranta got his first "real meal" for decades.

"He had steak. A manly meal. Steak - and probably everything else on the menu," his sister said.

Later that day, Ranta began feeling unwell and was rushed to the hospital.

Ranta was sentenced to 37 years in prison for the 1991 murder of Brooklyn Rabbi Chaskel Werzberger, who was shot dead in a botched diamond robbery in Williamsburg.

Despite the absence of physical evidence, Ranta was found guilty. The district attorney's conviction integrity unit reopened Ranta's case in 2012 after prosecutors asked defence attorneys to notify them of questionable cases.

The district attorney found serious problems with investigations conducted by detectives in Ranta's case. A man who was just 13 at the time recalled being asked by a detective to "pick the guy with the big nose" out of a line-up.

Later a drug-addicted woman testified that her husband had confessed to the killing before dying in a car crash, but a judge dismissed her testimony as untrustworthy.