There oddly wasn't a ton of coverage over his heart issue other than letting everyone know a few months back that he had suffered a "cardiac event", but I'm starting to get the sense that things were pretty dire for him at one point. I always hate when retirements like this happen, and you end up realizing after the fact that you watched his last match without even realizing it, but I'm glad he's doing better now.
HHH may not be on wrestling's Mt Rushmore, but it can be argued that he's had every bit as much influence on wrestling as many of the all time greats. Legendary singles career, legendary stable in DX, and his work in Evolution and NXT was huge too. I know there are wrestlers out there that don't like him because they feel like he plays favorites a lot, but HHH has an eye for talent, and he's been right about things a hell of a lot more than he's been wrong