This was actually a text with some problems some time ago. The verb that comes after 'the heart' should be one that expresses fastness, acceleration, 'anger' of the heart - 'heart runs' also expresses it, but it's kind of weird to say a heart 'runs' and it can also be understood like the heart is running to some place, when it's not what the text means. It's just 'static speed', nervousness caused by anger or disappointment.
Hi Freya, sorry to bother you.
I think we can solve the problem of "s'emballer" with the Italian verb "scalpitare" (which is "paw the ground" in English), which gives that idea of "static speed" and fits with the place complement. I know it's not the same as "s'emballer" (in Italian "imbizzarrirsi", but it's the only solution I've figured out...