pitty-pat
1. [ adverb ] as of footsteps
Synonyms: pitty-patty pitter-patter pit-a-pat
Examples:

"he came running pit-a-pat down the hall"

2. [ adverb ] describing a rhythmic beating
Synonyms: pitty-patty pitter-patter pit-a-pat
Examples:

"his heart went pit-a-pat"

Similar spelling:   pitty-patty
  pit-a-pat