Calling it “a pretty tough and emotional day” in a video posted on social media by the Capitals, Henrik Lundqvist announced Thursday that he will sit out the upcoming NHL season because of a heart condition.

The man known as “King Henrik” said he has been undergoing various tests on his heart “for several weeks.” He joined the Capitals about two months ago, after 15 years with the Rangers.

The 38-year-old from Sweden was bought out by the Rangers and signed a $1.5 million, one-year deal with Washington in October to try to earn his first Stanley Cup — and try to help Alex Ovechkin win a second.

Lundqvist said Thursday he had been excited to play with the Capitals, a team he said “checked every box” when he agreed to go to Washington.

The plan had been for the longtime face of the Rangers to share goaltending duties for the Capitals with 23-year-old Ilya Samsonov. The Capitals added Lundqvist to take the spot of 2016 Vezina Trophy and 2018 Stanley Cup winner Braden Holtby, who left to sign an $8.6 million, two-year deal with the Vancouver Canucks.

Lundqvist has appeared in 887 NHL regular-season games, plus another 130 in the playoffs, and he came close to a championship in 2014, leading the Rangers to the Cup Final. He lost postseason series to the Capitals in 2009 and 2011, then eliminated them in 2012, 2013 and 2015.

But he hadn’t participated in the playoffs with New York since 2017 until two games in the qualifying round of the expanded, 24-team playoffs this past summer.