My "sources" have confirmed that he was in SVT and not something more serious. That being the case, the standard workup would include an echocardiogram to check the chambers and valves of the heart, lab work to rule out electrolyte problems as per TheHeat's post, thyroid blood test to rule out hyperthyroidism(overactive thyroid), and a holter monitor to see if he is having short episodes of this rapid rhythm that he isn't aware of (such as while asleep.)Also lab tests to make sure he didn't have a heart attack that set this off(very unlikely in his case.) If all is normal they might run him on a treadmill and see if they can induce this rhythm to start again. If all is normal, they will probably put him on some medication and see what happens. If he has had this before they may proceed with the EP study mentioned in my previous post. Bottom line--he will probably be out of the hospital this weekend and back in action whenever he feels up to it. This can really freak some folks out and many patients like to take some time off to get their heads together.
I'll update if I get anything more. Later, Dr Dave