The Sanders campaign Wednesday canceled his upcoming schedule after 2020 Democratic presidential hopeful Bernie Sanders suffered chest discomfort and underwent a heart procedure for a blocked artery.

“During a campaign event yesterday evening, Sen. Sanders experienced some chest discomfort,” Sanders senior adviser Jeff Weaver said in a written statement. “Following medical evaluation and testing he was found to have a blockage in one artery and two stents were successfully inserted.”

Sanders, 78, I-Vt., the oldest of the candidates seeking the Democratic presidential nomination, is said to be talking and in good spirits. Sanders had a very active campaign schedule, typically holding multiple events and different cities daily. He had planned a trip to California in coming days after stops in New Hampshire and Nevada earlier this week and then to Iowa for the weekend. Events were canceled indefinitely.

It was not announced where Sanders was hospitalized.

The news came a day after the Sanders campaign announced a $25 million fundraising total for the third quarter.

A campaign aide told the New York Times Sanders “feels better than ever because that’s how people feel after they get a stent and there’s more blood flow.”

The campaign had been planning to air the first campaign television ads in Iowa Thursday but began canceling them Wednesday.

Sanders’ rivals for the nomination sent their best wishes and expressing confidence he would recover fully.

Sanders is 5 years older than President Trump and 3 years senior to leading Democratic presidential contender, former Vice President Joe Biden. Until Tuesday night, he had projected a vigor uncommon to people his age.

A stent is a wire mesh tube that props open an artery clogged by fatty plaque. During the 2016 campaign, Sanders released a letter from his doctor indicating he had no heart disease.

In other Democratic campaign news, Sen. Kamala Harris of California urged Twitter to suspend Trump, citing tweets she said put people’s lives in danger.

In a letter to Twitter’s Jack Dorsey, Harris pointed to a series of tweets about the whistleblower whose complaint led to the House impeachment inquiry, a tweet inviting “civil war” if the president is removed from office and a tweet describing the investigation against him as a “coup.”

A White House spokesperson told CNBC Harris is just trying to silence a political opponent.