Luxembourg cyclist Kim Kirchen was hospitalized following an apparent heart attack after the seventh stage of the Tour of Switzerland, Team Katusha's sports director said Saturday.

Serge Parsani said that the rider felt dizzy at the team hotel on Friday night and was sent to the Zurich University Clinic.

"We were all together when it happened yesterday evening at the hotel," Parsani said. "He felt really bad and we immediately sent him to the hospital. We are now waiting for the test results."

Parsani said that Kirchen, 31, is in stable condition and undergoing medical tests. He added that the one-day classic specialist experienced similar problems in the spring.

Kirchen, who wore the Tour de France's yellow jersey for four days in 2008, also won the Walloon Arrow that year.

He was 48th overall in the Tour of Switzerland before his withdrawal, trailing race leader Robert Gesink of the Netherlands by 19 minutes and 46 seconds.