What Do Fluttering Sensation In The Chest And Missed Heart Beats Indicate?

I have episodes of fluttering and missed Heart beats. I m fit, BMI is 20. I have pitting edema in my legs, mainly the right one. This has going on for over a year. For the past few months it s got increasingly worse. Finally am seeing a cardiologist as of last week. Stress test was good. Echo was good. I also wore a 24-hour monitor. I don t believe I had an episode during that time. Waiting for the results on that. I have these episodes that last anywhere from 5 minutes to several hours and it s terrifying. I just want answers and I wish someone would know what is happening. I feel like my heart is trying to get back into rhythm during these episodes. Do I need a pacemaker? Could this have anything to do with the edema? My blood work only shows that I am anemic. Kidney and liver function is good.