Diltiazem for SVT prevention?

[KJVW]

Just wondering if anyone here is taking diltiazem daily to prevent SVT? If so, how have you found it?

A tiny bit of background, I was diagnosed with thyroid disease (graves') last year and before I had my thyroid removed I developed ectopic beats which were irritating but not associated with fainting etc etc. After I started taking thyroxine I began experiencing palpitations several times a day, a holter monitor showed that they were runs of SVT. I was prescribed diltiazem to tide me over until I could see the electrophysiologist. By the time my appointment came around the SVTs had stopped (although the highly irritating ectopics continue) and he felt that taking diltiazem long term rather than having an ablation would be a good option.

I'm tolerating the diltiazem well, the only side effects are I seem more forgetful, which might not be related I suppose!! I'm in my 30s so could potentially be taking diltiazem for 40+ years... I've rooted around for studies on long term diltiazem use and not found much, the general consensus is, it's safe. Any advice or experiences would be greatly appreciated!