Why is it that so many assume this parody of a "study" is in any way valid?
Look. Just because someone somewhere started calling the brain fart of some kid a "study" doesn't mean you have to give it any credibility.
Sure, it's quite possible to interrupt the operation of a pacemaker briefly by, for instance, having your phone right next to it when someone calls you. It'll still work, it's just that it might not work in a mode that you would consider optimal, for a short while.
But the ouput from a shitty little iPod is nothing compared to a phone.
And EMI is not a "black art". Any electronics designer worth anything knows how to minimise it. It's only the people who haven't learned yet that will tell you so. And since pacemakers have a metal shell, it's highly unlikely that the frequencies that might be emitted from any little player will penetrate the shell (with an amplitude that actually matters). They can, by a far stretch of the imagination, disrupt measurements. But even that is pretty far-fetched.
Do you want to bet that the kid stuck the iPod between the pacemaker and the readout equipment?