Silvio Berlusconi to have urgent heart surgery after attack 'that could have killed him'

'He was in a really serious, worrying condition and he knew it'

Mr Berlusconi has worn a pacemaker since he was 70 (AFP/Getty Images)

The former Italian Prime Minister Silvio Berlusconi will undergo heart surgery to replace a defective aortic valve, his doctor has said.

The 74-year-old billionaire businessman was admitted to hospital on Monday suffering from what his doctors described as a cardiac deficiency.

His personal doctor, Alberto Zangrillo, said Mr Berlusconi "risked dying", suggesting his condition is more severe than previously revealed by friends and family who have been visiting the former premier at Milan's San Raffaele clinic since his admittance.

Dr Zangrillo said a team of doctors ran a number of tests and diagnosed a severe case of aortic insufficiency, which involves a leaking of the aortic valve of the heart, causing blood to flow in the reverse direction.

Mr Berlusconi, who has worn a pacemaker since he was 70, will undergo the four-hour surgery by the middle of next week, after which he will be in intensive care for one or two days before a month-long period of rehabilitation.

“He was in a really serious, worrying condition and he knew it,” Dr Zangrillo told reporters on Thursday, adding he was being treated "like all other patients".

According the Mr Berlusconi's doctors, there is a two per cent risk of mortality tied to the operation.

Earlier on Thursday, a spokeswoman for his Forza Italia (Go Italy!) party denied reports Mr Berlusconi would need an operation.

Mr Berlusconi served as prime minister four times, but has since been convicted of tax fraud and bribery .

Since leaving office in 2011 his political influence has declined and his party received a mixed result in Sunday's local elections, with his mayoral candidate in Rome coming fourth.

The election campaign is said to have taken its toll on Berlusconi and his doctor said he would benefit from quitting politics.

Additional reporting by agencies