The Liverpool manager had been rushed to hospital on Saturday after complaining of chest pains at half-time in Saturday's game with Leeds.

After a lengthy operation, Houllier has now regained consciousness and has also been taken off a ventilator.

A spokeswoman for the city's Cardiothoracic unit emphasised Houllier had not had a heart attack, and that his heart was in "excellent condition".

She added: "Mr Gerard Houllier sustained acute dissection of the aorta.

"The operation took over 10 hours and we are pleased to report that so far the outcome has been extremely satisfactory."

It is not known whether Houllier will be allowed to watch Liverpool in Champions League action when they take on Dynamo Kiev on Tuesday.

But an official statement on the club's website said: ""We stated that the next significant step would be for Gerard to be taken off the ventilator.

"We are delighted to say this has now happened and we are encouraged by this positive progress."

Houllier's assistant, Phil Thompson, who has been placed in temporary charge of team affairs, said news of the manager's improving condition had given the team a big boost.

"The players were really buoyant when we told them because it happened at exactly the right time for the lads to know something like that," he said.

"They know I expect them to get a good result for themselves, for Gerard and for the club."