Pacemaker twiddler's syndrome: a case report.

A patient with a dual-chamber pacemaker presented with rhythmic contractions of her right hemidiaphragm. The atrial lead of her pacemaker had retracted into the right subclavian vein, causing pacing of the right phrenic nerve. The cause of the lead displacement is unknown, but may have resulted from unintentional manipulation of the pacemaker generator pouch by the patient, the so-called Pacemaker Twiddler's Syndrome.