The rhyme scheme is abbaabba cdcdcd.
The poem is written in a loose iambic pentameter, consisting of five ("penta") pairs of unstressed and stressed beats ("iambs")
Lines 3, 4, 5 and 12 are iambic pentameter
The last line is the only one with a consistent da-DUM beat, the mighty heart beating, the city asleep (Owlcation, 2020).