The forward also revealed he believes the Rossoneri would have won the title had they not been beset by injuries and that Pato is second only to Messi in terms of talent
The AC Milan forward was forced to undergo an emergency heart procedure after taking ill in the aftermath of his club's 3-2 victory over Roma in the Italian capital.
Cassano made a rapid recovery from the surgery and returned to action last month, but the Italy international has admitted that he had initially doubted if he was going to come through it.
"I was fine, I was happy to come off the bench [against Roma]," the Italy international explained in an interview with Milan Channel.
"On the plane I felt good. All of a sudden on the bus at the airport, after we landed, my head started to spin; I could not see well with my left eye.
"The doctor told me: 'I'll take you to the hospital.' I did not want to go and we argued over it for half an hour.
"When we decided to go to the hospital, I started to have trouble speaking. I thought but the words would not come out. At that moment, I started thinking about my son and seeing him one more time" Cassano said, before attempting to fight back the tears.
Turning his attention to his season's Serie A title race, the former Sampdoria man argued that the Rossoneri would have run away it had they not had been plagued by injuries.
"Firstly, we have to congratulate Juve," Cassano stated. "But we had a billion injuries, without which we would have won by a six or seven-point margin.
"We are by far the strongest team in Italy but we did not have consistency like Juve. But Milan went out to win it all, and we will give our all next season too."
Cassano admitted that he is desperately hoping that Alexandre Pato will be a part of that drive. The Brazilian has been beset by thigh problems this season and has also been linked with a move to Paris Saint-Germain, but Cassano believes Milan would be foolish to allow him to leave.
"When I speak about Pato I always do it because I think he is potentially the second best in the world behind [Lionel] Messi and hopefully he will come back stronger than before," he claimed.
Cassano, though, is now hoping to get more minutes under his belt in Milan's final Serie A outing of the season, against Novara on Sunday, before Italy coach Cesare Prandelli names his squad for Euro 2012.