Changes to ecg results?

Over the last year I have fainted once and then have four other occasions where I have almost fainted, it comes on suddenly and I get very sweaty, weak, pale and have spots on my vision, to stop myself from fainting I have to sit down. This has happened for no reason once I was standing in line in a store another time I was at the gym. I went to the doctors where they took blood tests and conduced an ecg, bloods came back normal, however, my ecg have to be looked at by 3 doctors and due to there being changes to my ecg this time round, had an egc the first time I fainted as I got taken to a&e which came back normal which was around a year ago now. I'm waiting to be refered to the cardiologist but am just wondering if anyone may know what could possibly be wrong?
Changes to ecg results?
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