I'm going to prescribe something you may think is crazy, but it may be your cure. The irregular heartbeat is what clued me in. You probably have a potassium and magnesium deficiency. These two deficiencies can cause itching and crawling sensations on your skin and heart rhythm irregularities. Don't say "But I eat bananas," because there isn't enough potassium in a banana to help you. Buy some 99mg capsules. Take three in the morning and three at night for a month. Also buy a calcium-magnesium-zinc supplement and take two every night at bedtime. These are very cheap supplements. I had these deficiencies and it gave me the exact same symptoms you have. Also, start rubbing coconut oil all over where the itching is. If it's a skin parasite of some kind on top of the deficiencies, it will help ease the itching.