Bernie Sanders — one of the Democratic presidential candidates — has suffered a heart attack.

The 78-year-old was at a campaign event on Tuesday when he experienced chest discomfort and was taken to a hospital where he was diagnosed with a heart attack, his campaign said.

The senator was transferred to Desert Springs Hospital Medical Centre where doctors inserted two stents to open up a blocked artery in his heart, according to a statement from the Las Vegas doctors.

The doctors, Arturo Marchand Junior and Arjun Gururaj, said the rest of his arteries were normal.

A blocked artery can cause a heart attack, which just means that an area of the heart is suffering and in danger of damage because it is not getting enough blood or oxygen.

An artery-opening procedure like the one Mr Sanders had, and placing stents, which are tiny scaffolds to keep the artery open, restores blood flow and helps prevent future problems.

The statements from Mr Sanders and his doctors do not indicate whether his heart suffered any permanent damage, or the extent of any.

The doctors said the rest of his stay before being discharged on Friday was “uneventful with good expected progress”.

The campaign also released a statement from Mr Sanders where he thanked the doctors, nurses and hospital staff.

“After two and a half days in the hospital, I feel great, and after taking a short time off, I look forward to getting back to work,” he said.

He was expected to return to Vermont.

This marks the second time in two months that health problems forced r Sanders to cancel campaign events.

In September, he backed out of some appearances in South Carolina because he lost his voice. His campaign said at the time that Mr Sanders felt fine.

As the oldest candidate in the Democratic 2020 field at 78, Mr Sanders has sometimes jokingly referenced his age on the campaign trail.

He is one of three septuagenarians who are leading the crowded race and have sparked questions within the party about whether Democrats need to coalesce around a younger leader.

Current president Donald Trump is 73.–PA