also pitter-pat, 1520s; imitative. As a noun from 1580s.
Examples from the Web for pit-a-pat
There it was again, pit-a-pat, pit-a-pat, very soft and coming nearer.The Adventures of Old Man Coyote|Thornton W. Burgess
My hand trembles, and my heart goes "pit-a-pat" as I think of being present at the trial.Cora and The Doctor|Harriette Newell Baker
Its feet went pit-a-pat, pit-a-pat, with a horrible clanking noise like chains.Legends of Longdendale|Thomas Middleton
Rain was falling, pit-a-pat, and he was without cover on a wet patch of grass.How to Tell Stories to Children|Sara Cone Bryant
My heart was going pit-a-pat, pit-a-pat, and I could hardly breathe, but I had no sensation of pain except in my chest.High Adventure|James Norman Hall