When I was 21 this song either saved my life or ruined it; I’m still not sure which, but that’s a clammy tale.  Let’s get to the rhymes.

“Heart Of Mine” consists of five verses, all of which begin and end with rhymes. The first and last verses are all “i” rhymes.  This is fitting as this is a song with an internal conflict between one’s heart and mind, all about the battle raging within the “I” of the song.  An antithetical rhyme like “home”/”roam” enforces this, as does the rhyme at the end of the second verse

Don’t put yourself over the line
Heart of mine

because indeed if the intent was to stick to the pentameter 10 syllables, one syllable has sent it over to eleven, overreaching, beyond control of the line, over the line, like this heart that won’t stop desiring no matter what the mind tells it.

And the instruments creating the music in the song battle as well.  The percussion, the drums are the beating heart, sometimes drowned out or overcome by organ, piano (that’s Dylan on the studio version), or Ron Wood’s guitar scratching, so memorable in this song.  But like the heart that gets louder and louder by the end in Poe’s “Tell-tale Heart” the drums become more demanding, more prominent, as does a heart bursting to fulfill desire, lust, love, call it what you will.

The drum make it’s presence known after Dylan sings that “over the line” line, but especially after

Don’t untie the ties that bind
Heart of mine

It’s as if the heart can put up with the rest of the mind’s admonishments, but not untying ties that bind, oh no, that will not do.  By the end, the drum matches organ and piano. Listen for it.  Nothing can stop a heart wanting to be fulfilled.

Here’s a live version, outdoors, Dylan’s hair blowing in the wind, from I don’t know when but looks early 80ish.