ドクッ

adverb taking the 'to' particle

with a heavy thump; with a thud; with a palpitation

Mimetic adverb describing a single heavy, dull impact or a sudden strong heartbeat. Often used with と.

• 心しん臓ぞうがドクッと大おおきく脈みゃく打うった。

  My heart gave a heavy thump.

• 重おもい荷に物もつが床ゆかにドクッと落おちた。

  The heavy luggage fell to the floor with a thud.