Please avoid PPI's and anti acids. First instead try increasing your stomach acid through betaine hcl + pepsin with high protein meals, and use ox bile for high fat meals. You can combine the two. Dosing will depend on the individual - it's something you will find out with trial and error what you personally need. In my experience, acid reflux can be completely cured through this method and you will only assist nutrient asborption, you can only benefit through this method. If you want to band aid temporarily fix your reflux with anti acids - okay, go ahead, continue. I can only offer hands on experience and advice, I suffered for a long time with your symptoms.
(Edit after reading, take the above posters advice and check the afib and heart burn is not related before embarking on taking my suggestions for digestion issues)