"心脏急速跳动" can be translated into English as "the heart is pounding rapidly" or "the heart is beating wildly".
Both expressions convey the idea of the heart beating quickly and forcefully, often due to excitement, fear, or physical exertion. You can choose based on the specific context or the nuance you want to express. For example:
"My heart is pounding rapidly as I wait for the exam results."
"After running up the stairs, her heart was beating wildly."