Twiddler's syndrome is a rare condition of pacemaker rotation; when associated with unipolar pacing it could provoke extracardiac muscular stimulation. We report a case of an obese woman who unintentionally reversed her triple-chamber, dual-site unipolar atrial pacemaker, implanted for the prevention of paroxysmal atrial fibrillation. The extracardiac pectoral stimulation was due to unipolar atrial stimulation. The polarity mode was not programmable and output reduction was unsuccessful. Thus, the problem was resolved noninvasively by means of external manual rotation of the pacer. At 24 months of follow-up, the patient was still free of symptoms.