From LearnTheHeart.com's Twiddler's Syndrome review on the Cardiology Reviews and Definitions page.
Twiddler’s Syndrome occurs when a patient with a permanent pacemaker manipulates the pulse generator usually by turning it multiple times. This results in the leads becoming dislodged and malfunctioning. The manipulation is most frequently done subconsciously in the setting of dementia or during sleeping hours. Chest x-ray is very helpful to make this diagnosis as the leads can be seen twisted.
Treatment includes repositioning of the leads and patient education. Physical restraints may be needed to prevent recurrence. Below is a chest x-ray from a patient with Twiddler's syndrome. Note the twisted leads near the pulse generator. The right ventricular lead has also dislodged into the right atrium.