Wetzikon, Switzerland - Former Luxembourg national champion Kim Kirchen is in a stable condition after being placed in an artificial coma following a heart attack, his Katusha team said on Saturday.

Kirchen, who finished seventh overall in the 2007 Tour de France, had been competing in the Tour of Switzerland when he felt unwell and was hospitalised overnight on Friday in Zurich.

"Kim Kirchen is in a stable condition after the heart attack he suffered overnight yesterday (Friday)," his team said in a statement.

"The Luxemburger was placed in an artificial coma to better evaluate his condition. The rider must remain in this condition for at least another 24 hours."

Kirchen, 31, suffered respiratory problems at the end of March and had been out of action for a month.

"He felt bad so the team doctor sent him to hospital," said team sports director Serge Parsani.

"He already had a similar kind of problem two or three months ago. We don't know (what the diagnosis is)."

Kirchen is primarily known as a one-day race specialist and has notably won the Fleche Wallonne in 2008. He is also a two-time national champion in both road and time trialling.

He had been in 48th position after seven stages of the Tour of Switzerland, 46sec behind leader Robert Gesink. - AFP