I have afib. My onc wanted me on Kisqali, I said no because of the possible heart issues.
I switched oncs.
Im on exemestane and Verzenio.

I found with my afib, dehydration was an issue, especially in summer.
I have some grey Celtic salt i put under my tongue, about 4-5 little chunks, keep them in my mouth for about 10 seconds then drink some water.. I do this when I know im going out in the heat as a preventative measure. I also take it when my lips feel dry.
It has helped with hydration quite a bit and my afib episodes are minimal.
I bought the cheapest Kardia recommended by my cardiologist.( Bestbuy) I carry my ipad and the Kardia with me at all times as well. Very helpful to record the ekg reports and monitor the duration.
I keep a prescription bottle filled with the Celtic salt in my purse and carry it with me at all times. Dehydration creeps up on me. I also carry an 8 ounce bottle of water in my purse at all times with the Diltiazem.
For me, the choice was cancer over the heart.