When one is confronted with a very complex medical puzzle like you have,
it can inspire alot of anxiety. One can read things in the literature and without medical training or background one can become very alarmed. I only bring up the low potassium issue with you, because it is very rare. There are just so few papers on it (I could only find one, and it was OLD).

Living with palpitations for as long as you have, is painful. The feelings lead to fear...and now there is anger because you were not listened to.

I think your website is doing a good job. What rose and I do which is similar is try to put the data into context for people. We want to educate, and not further alarm. People who are ill already are already alarmed.

Now to move on the your EFA deficiency. I think you should be doing something aggressively to raise your Omega-3 status ASAP. Low EFA status causes heart beat irregularites too. Males are not efficient in converting alpha linolenic acid in food, to the long chain EFAs EPA and DHA. Females who are intended to reproduce and pass these EFAs to the fetus convert much higher.
I saw a ratio once. Males convert about 4%, and females about 20%.
So after you were born, you have to rely more on your DHA that you received from you mother, than females do.
Basically if you are so low in these, you are lucky to be alive now. You just have to have them. Either from eating salmon or taking fish oil. So I hope you are doing that right now.

The body tends to conserve potassium whenever possible. But there are genetic errors with potassium use--one is called Periodic paralysis. You can look that up. And the other is loss thru the kidneys which is renal tubular acidosis (which can be mild and not really obvious). You need to eat at least 4.7 grams of potassium a day, so people who do not eat properly can get low.
For example...a can of V8 juice 12oz has the same amount of potassium in it as one of your SlowK tablets. Not many people understand how some foods can easily provide potassium. 1/2 cantaloupe has 1,400 mg of potassium!

And you can have irregular heart beats if you are low in magnesium. This is very common, and estimated that 7 out of 10 people do not get enough magnesium daily. I have a magnesium thread here that you can read. It covers the subject quite well. So I hope you look at it.