How worried should I be about my cat having an enlarged heart?

I just brought my cat back from the ER for unrelated reasons, but while he was there he got an X-ray. Then in the notes when leaving they had put down that he might have an enlarged heart but they're not sure if he will grow into it (he's just recently turned 1). Is this something I should be worried about? If so, if anyone has dealt with it... what would I even look for?

Nothing to be concerned about at this time. If you notice depression, lack of appetite, or weakness those could be signs that it is more serious now and needs a second look. But if there are no symptoms then you are in the wait and see stage due to his age. Some kittens/cats will grow out of heart related potential problems.

At his next annual exam you'll want to ask the vet to check for a murmur and take x-rays to compare with the x-ray from this week (on which note, always ask for a copy of all test results and x-rays from your vet , even just a cell phone photo works. Losing that stuff in sudden moves, unexpected changes at vets, or random acts of God is not fun). If it continues to be a concern at that point you would then talk to your vet about preventative steps you can take to minimize the risks of heart disease and related problems.

Now might be a good time to start a little vet fund going too in case it does become something. You don't want to be like me with a huge debt from vet bills. Although CareCredit, if offered where you are, is great for that so long as you pay it off in the promotional period. 

Yeah, my luck with my cats health isn't too good. He actually just had surgery for a foreign blockage 2 months ago which maxed my CareCredit out. But I will start to save money, but hope that he will grow out of it. Thank you!!!