I thought the people in the ads were dancing. Turns out they were convulsing.

Heart-ache — literally:

iPods can cause cardiac implantable pacemakers to malfunction by interfering with the electromagnetic equipment monitoring the heart, according to a study presented by a 17-year-old high school student to a meeting of heart specialists on Thursday.

The study tested the effect of the portable music devices on 100 patients, whose mean age was 77, outfitted with pacemakers. Electrical interference was detected half of the time when the iPod was held just 2 inches from the patient’s chest for 5 to 10 seconds…

In some cases, the iPods caused interference when held 18 inches from the chest. Interfering with the telemetry equipment caused the device to misread the heart’s pacing and in one case caused the pacemaker to stop functioning altogether.

The study was held at the Thoracic and Cardiovascular Institute at Michigan State University. The results were presented at the Heart Rhythm Society annual meeting in Denver.

The good news is, there probably isn’t much overlap (yet) between the iPod market and the pacemarker market. Exit question: Is this good PR or bad PR for Apple’s newest competitor?