Philip, 90, was airlifted from Sandringham in Norfolk to Papworth Cardiothoracic Hospital in Cambridge after he suffered chest pains, The Daily Telegraph reported. Doctors there found he had a blocked artery and Friday performed "the minimally invasive procedure of stenting."
Saturday, a Buckingham Palace statement said the Greek-born duke of Edinburgh had a "good night" and was visited by Queen Elizabeth II, 85, and son, Edward, at Papworth Hospital, but remained under observation, the BBC said.
The queen and her husband were entertaining an unusually large group after a year in which two of their grandchildren married. The duke went to Sandringham Monday while the queen followed the next day, taking a public train from London.
Philip started to slow down his public life as his 90th birthday approached in June, cutting back on events and resigning as president or patron of several charity organizations. He has been fairly healthy for most of his life although he was hurt several times playing polo.
Arthritis in his right wrist, a result of an old polo injury, was aggravated by years of handshaking, the reports said.
The royal couple have a busy schedule in 2012 as the queen celebrates her Diamond Jubilee of 60 years as monarch.