ER said ECG looked fine but scan image said otherwise ABNORMAL

No, but follow though with everything they other and if you have any more issues run don’t walk to the closest ER. bring your papers with you, also pencil, a Ziploc bag and some puzzles cause I think you’ll be there for a number of hours.
I wish you the best as I also had something similar three years ago and they found the problem.

I don't know that worrying will help. So, no, don't worry. Instead, if you're the least bit interested, start reading about atrial and ventricular hypertrophy, tachyarrhythmias and their treatment. The better prepared you are to absorb, and to question, information caregivers and experts who want to put you through diagnostics and treatments ask of you, the more likely you are to feel empowered and on top of things....at least to the extent any patient can feel on top of a new and unpleasant diagnosis.

The only truly dangerous arrhythmia needing a call to 911 is ventricular fibrillation, and it's unlikely you'll ever make that call yourself. Someone will be standing over you and dialing. All the others, ventricular and atrial tachycardia, SVT, atrial fibrillation, etc, can all be dealt with initially at an ER, but you can drive there or be driven there...you don't need an ambulance and EMTs to keep you alive. Of course, if you are feeling very faint, generally unwell, out of breath, then it might be best to call an ambulance.

Again, this is naturally worrying, but you don't have to get yourself worked up while waiting for the cardiologist's appointment. Believe me, I've been 'there', with you, as have millions of others. I have been on my back for hours in an ER, all hooked up, blood drawn, and within five-eight hours my heart reverts to NSR and I slink home. Three weeks later, same thing, same atrial fibrillation, same outcome. I hate it, but it hasn't killed me, and the forumites at afibbers.org have told me plenty of times....most arrhythmias are not emergencies, and most will not kill you. They'll just make you miserable if you're symptomatic while it's happening.

General rule to follow: if any device or trained person records a heart rate of yours that runs 100 BPM or more, and that lasts up to 24 hours, then get to emerg soonest and get looked after. And good for you if you manage to tough it out that long...I never could. Yes, I'm a wimp.

At some point you may be referred to, or advised to seek the services of, an electrophysiologist. An EP is a heart specialist looking into electrical disorders, which an arrhythmia is. I would strongly counsel you to see one for at least an initial look a you and a consultation to determine what, if anything, should be done by such a specialist. You may find that they can help you a great deal.

@gloaming thanks for all the info and encouragement hope you are doing better now!

@minnesota10 Thank you for responding and hope you are doing better now!

I had an ECG a couple years ago after having had an ablation (~4 years ago), and mitral valve repair (coming up on 2 years ago). The cardiologist said all is good, but as with your experience, the scan said I was in heart failure. The next time I saw the cardiologist, he said that sometimes the machine is not very good a reading the ECG.
Since you are still having symptoms, I would get in when you can and follow up as recommended.
All the best.

@aard Thank you so much for the info and responding. Going in tomorrow morning! Hope you are better now.

@cltotten1 I am doing swimmingly, thanks. I had two catheter ablations where they make scar tissue in circles around the pulmonary vein ostia, their mouths, where they each, four of them, empty oxygenated blood into the left atrium (that location accounts for 90% of all patients' atrial fibrillation, so it tends to be the first attempt at busting the arrhythmia). The scar tissue doesn't affect the heart much at all, but it is impervious to the rogue electrical signals emanating from those ostia. Dam around each vein, no signal can get out into the endothelial lining of the atrium and cause the myocytes to beat chaotically...which is what fibrillation is.

First attempt failed (there's a statistical failure rate of all first, or index, ablations of 25%, regrettably.) Second seven months later has had me in NSR for just under three years now. More statistics: most ablations fail in time. Some within months, some many years later, with the heavy majority going a few years at least. For symptomatic AF sufferers, that's a gift of immense value. I'll happily take three years free of AF, and then go see my EP for a re-do.

@gloaming oh wow you have been through hell and back it sounds like. But also blessed! I’m learning a lot through each person who has been through similar things. I’m a pretty healthy 45 year old but do have heart issues in the family. Im hoping I caught it early and there is treatment to get me feeling well. Hang in there!