NEW YORK (AP) — JPMorgan said that CEO Jamie Dimon underwent emergency heart surgery on Thursday, March 5, but is recovering.

The nation’s largest bank by assets said in a message to its more than 250,000 employees that Greek-American Dimon was awake and alert following the surgery.

The New York bank said Dimon was stricken Thursday morning by an acute aortic dissection. That is when blood leaks through a tear in the inner layer of the aorta, the large artery that carries blood away from the heart to the rest of the body.

“He underwent successful emergency heart surgery to repair the dissection,” the bank’s message to employees said. “The good news is that it was caught early and the surgery was successful. He is awake, alert and recovering well.”

The bank’s co-presidents, Daniel Pinto and Gordon Smith, will lead its operations while Dimon recuperates, JPMorgan said.

Dimon, who turns 64 next week, is one of the nation’s most influential CEOs. He took over as JPMorgan’s chief executive on New Year’s Eve 2005, was named chairman of the board a year later and steered the bank through the financial crisis of 2008.

Dimon had a health scare in July 2014, when he disclosed he was battling throat cancer. The treatment was successful and Dimon said he was cancer free in December of that year.

JPMorgan Chase & Co. had a record year in profits and revenue in 2019, posting a full-year profit of $36.4 billion on revenue of $115.63 billion.