Twiddler's syndrome is a rare cause of pacemaker dysfunction characterized by coiling of the lead around the rotated generator. It is even less common for implantable cardioverter-defibrillator (ICD) devices. We describe a 44-year-old woman who underwent successful implantation of an ICD and three months later presented with left arm twitching. Chest radiograph demonstrated the unusual dislodgement of the atrial lead only and rotation of the ICD generator. The diagnosis of Twiddler's syndrome with solitary atrial lead rotation was thus established. The ICD pacing mode was switched to VVI, which resulted in cessation of muscle contractions. She later underwent atrial lead revision, untwisting and reanchoring of the ICD generator without any complications.