According to the Cinderfella trivia section at IMDb:
Lewis' musical entrance down the grand staircase was done in one take, a Lewis trademark. But his seven-second rush up the same 63 steps put too much of a strain on his heart and landed him in the hospital.
Confirmed by the Wikipedia entry:
In the Ball scene where Lewis arrives it was one take going down the stairs and one take going up. He ran the stairs in 7 seconds and collapsed at the top, where he was taken to hospital and ended up in an oxygen tent for 4 days. This delayed filming for 2 weeks.