I missed Raw last night and didn't catch up with the Lawler story until this morning (it's just coming up to 8am over here). It does sound like a heart related incident, but whatever the case, I really hope that Lawler doesn't plan on getting back in the ring, if this indeed turns out to be heart related. He has nothing else left to prove as a wrestler, having cemented himself as arguably the greatest southern territorial wrestler of all time and one of the greatest of all time overall.
When I first read the reports, I immediately began to think of Mitsuharu Misawa who fell into cardiac arrest in a match (Misawa had wrestled much longer than he should have from a physical point of view, having elected to stay on to help raise the profile of his his promotion - Pro Wrestling NOAH and to build new stars) and died following attempts to resuscitate him.
From what everyone is saying, Michael Cole handled things brilliantly, despite being emotionally rocked, a true testament to his professionalism. I hope King gets well soon and also sensibly reflects upon this recent incident objectively in regards to his level of physical performance in the future.