Prince Philip has had successful surgery for a pre-existing heart condition, and he is expected to remain in the hospital "for a number of days," according to Buckingham Palace.

The Duke of Edinburgh, who is 99 years old, moved from King Edward VII Hospital, where he had been getting treatments two weeks, to St. Bartholomew's Hospital last Monday. While the Palace did not detail Philip's actual illness, the latter hospital is famous for its cardiac unit.

Prior to his hospitalization, the doctors said that Prince Philip was feeling unwell for a few days; thus, he was advised for hospital admission as a precautionary measure. The Palace then released a statement saying that the Queen's husband was not suffering from a COVID-related illness, but he has an infection and has been responding well to the medications.

This has been the longest hospital stay for the Duke of Edinburgh in his entire life. In 2019, Philip almost missed out on the royal family's Christmas celebration as he had to be in the hospital for five days.

In 2011, Philip had an angioplasty and stenting after complaining of chest pains. Doctors learned he had a blocked coronary artery. According to Daily Mail, the duke has battled a secret heart ailment in the last 30 years.

Dr. Aseem Malhotra, a cardiologist who is not part of Philip's treatment team, said that his infection might have strained his heart, causing another blockage to his artery. The doctor said that this most recent procedure might have something to do with getting a second stent or a replacement stent, but he may have also had a pacemaker fitted.

Stents are like tiny tubes that allow for normal blood flow, and the insertion usually takes two hours at the operating table. The stents are then left inside the blood vessels as a permanent feature. In some cases, however, stents have to be replaced.

Insiders said that the duke, who will turn 100 years old in June, remains comfortable at the hospital. Camilla, the Duchess of Cornwall, said that her father-in-law has been slightly improving but he has moments of pain.

Prince Edward, the duke's youngest son, said that his father is doing OK and is raring to get out of the hospital to go home. Prince William also said that his grandfather is OK after Prince Charles visited him at the hospital. The Prince of Wales was the only member of the royal family to drop in on Philip during his first weekend at the hospital, sparking concerns that his condition may be serious.