Click image to enlarge
The story is this: an asymptomatic gentleman with an left ventricular assist device and implanted St. Jude biventricular implantable cardiac defibrilaltor had an episode of syncope and presented to the ER with this EKG.
Some interesting points are made in the discussion section of this case report published in Circulation (sorry, subscription required).
Definitely worth a read (and the link contains the answer).
Reference: Zalkind D, Aleong R, Sauer W, Nguyen DT. 'Unusual Fibrillation in the Emergency Department After Fall." Circulation 2011;123;e641-e642.