I'm one of those with arrhythmias before the surgery. No, surgery won't likely stop it. You need to know the cause or trigger for the problem, and it's probably not going to be a simple hernia or even a paraesophageal one unless there's some sort of physical tickling of the heart. (I'm no doc, just a patient, so this is only opinion and my personal experience.)
I wouldn't trust any new surgery that claims to cure a hernia without surgery. Somehow the hole has got to be sewed closed. Nissen-types still have by far the best outcomes statistically. If the hole is more than a couple of centimeters it's the only choice.
If you have reflux, why wouldn't you want it fixed at the same time?
I didn't just have a few PVCs; I had life-threatening tachycardia events, some of which sent me to the hospital when I couldn't get them stopped myself. My allergist had me keep a food journal and we found the list of foods that were triggers. (see multiple posts by many on food journals, challenge tests in the search box) I stopped eating them and the reflux stopped along with the tachy events, for the most part. I still had, and continue to have, minor events triggered by hard textures like a steak. My esophagus and stomach are sensitive to textures as well as chemical sensitivities. I get some PVCs after eating a little too much, like this morning's French toast - should have stopped at 1 slice.
I finally had to have the surgery (Nissen - Toupet variety) when I was in a bad wreck that pushed my stomach up into my chest. The surgeon said it wouldn't stop the tach, but I had no expectation that it would. If I consume more than the 2000 micrograms a day of sulfite that I tolerate I can expect to have a problem. But I don't have reflux anymore!
My gastroenterologist and my cardiologist didn't believe that I had a food intolerance, but my allergist sees them all the time. It's free and easy to keep a journal. It takes at least a couple of months, but if you can fix even part of the problem without surgery it's worth it.