ST. LOUIS (AP) — The husband of Sen. Claire McCaskill remains hospitalized in St. Louis, but the Democratic senator says on Twitter that he is showing signs of improvement.

Developer Joseph Shepard is hospitalized in an intensive care unit. McCaskill on Monday posted that he has “a very big heart but right now not working very well.”

In a Twitter posting Tuesday, McCaskill wrote that Shepard was still “in ICU but better.” Another tweet showed a brief video of his heart monitor and read, “Watching my husband’s heart in his room in ICU. Working better today.”

A spokeswoman for McCaskill says she has no additional information about Shepard’s condition beyond what the senator posted.

McCaskill and Shepard have been married since 2002. They have a home in suburban St. Louis.