After wrestling season, if you decide that you wanna include Creatine into your supplementation, then I would go with bulk CEE from NP and CreaPure. Personally, I've had great experiences with CEE in the past, however, I do not like CM. CreaPure is 99% pure German Creatine Mono. It's said to be the best and purest kind of CM you can find. It's sold at a very affordable price, too. I've tried very cheap brands of regular CM before. It made me retain so much water (hence, monohydrate), made me feel extremely bloated, and gave me some serious gas. CreaPure, however, shouldn't do this. CEE, on the other hand, made my strength increase and I leaned out. My muscles were solid. CEE didn't make me very thirsty. So, I know that it wasn't water weight. But, if you wanna start taking Creatine, then go with bulk CEE and CreaPure, both very affordable and effective. Wait until after you make it through wrestling season, though.
As for the heart; Yes, it is a muscle. We all know that. Before I started supplementing myself with Creatine (CEE, to be exact), I'd be able to run cardio before/after lifting, but not as long as I would've liked to. But, when I started using CEE, things changed. I was able to run, and run, and run. It was quite impressive, really. I'd originally be able to run for maybe 15 minutes before getting excruciatingly tired, but once I used CEE, I was able to run for about 30-35 minutes. I loved it. So, in a way, I'd say it does have a pretty good effect on endurance. Creatine, along with D-Ribose, help speed up, and increase the amount of, ATP production, which in turn, force feeds what you consume (proteins, BCAA's, etc.) into your muscles. I'm sure the same happens to the heart, as with all muscles.
With that all said; CEE and CreaPure. But, after wrestling.