Newcastle United manager Joe Kinnear was taken to hospital on Saturday after feeling unwell, dpa reported.
The 62-year-old was admitted to hospital "as a precautionary measure" and remains under observation.
Kinnear suffered a mild heart attack in March 1999 when he was Wimbledon manager, a job he later stepped down from because of his health.
He later managed both Luton and Nottingham Forest but spent four years out of the game before taking over at Newcastle in September of last year.
Kinnear's assistant, Chris Hughton, will take charge of Newcastle at The Hawthorns.