QT is different from angina. QT involves the nerve conduction and not constricting blood vessels.

You could try the Morton's Epsom lotion. Sometimes oral doesn't get absorbed as much as we think or would like.
You wouldn't need much -- I'd put a quarter dollop divided on both arms, along the inner wrist and inner arm up to the elbow.

You wouldn't need much. If you see it works well, then you could skip the oral and just use a bit more lotion instead. Applying to thin skin over visible veins would be best for systemic absorption.
I do use it on large muscles when they are strained and hurt.
And I do my ankles and instep sometimes now. (my swollen foot used to really respond to it, but since it is not swelling lately I only do my arms.).

WalMart and Amazon have this for a very low reasonable price.
I get ours in the WalMart near us off the shelf. (online is not necessary). You can check availability of Morton's online at WalMart's website. They will give you "in stock" or not right there for the store in your zip code closest to you. It is found in the first aid section.

Since you are not testing low for mag, and you don't have long QT on your EKGs.... the Elavil should be okay. It really only is risky in high doses like the old days when it was used as an antidepressant. Its cardio effects showed up in suicide overdoses, initially in fact. This is one reason the SSRIs became so profitable so quickly...I went to a CE on it from Lilly when Prozac came out and the guest psychiatrist mentioned this safety issue as the most important reason to switch patients off the tricyclics which were very popular then. Elavil was not so popular by then, and it was Tofranil which had slightly fewer drowsiness effects.