The Frenchman, 63, also expressed his gratitude for the messages of support he has received from Villa fans as well as from friends far and wide.
"I am extremely touched by all the messages I have received and by the reaction of people throughout the world of football. It has been overwhelming actually," he said in an official statement.
"I'm especially grateful to the Villa fans for their genuine concern and encouragement and to the fans of clubs up and down the country. There has been a groundswell of goodwill and I appreciate this so much."
It was confirmed that the cause of Houllier's chest pain was a dissection of the descending aorta, which occurs when a tear in the inner wall of the aorta causes blood to flow between the layers of the wall of the aorta and force the layers apart.
Club doctor Dr Mark Waller added: "All the tests have confirmed that his heart is working perfectly. We are extremely encouraged by Gerard's improvement over the past six days and we now anticipate that he will be discharged from the coronary care unit at the Queen Elizabeth Hospital within the next three to four days."
Source: PA
Source: PA