Sleep (Vagal)–Induced Atrial Fibrillation
A 41-year-old man with history of paroxysmal atrial fibrillation underwent routine Holter monitoring for symptoms of palpitations at night. The Holter recording from a person with a regular heart rate is shown in the Figure (A). The Holter recording from our patient (Figure, B) showed initiation of atrial fibrillation with the onset of sleep and spontaneous termination on awakening. This heart rate trend over the 24-hour period illustrates inversion of the normal circadian rhythm, with evidence of a slower heart rate during the daytime hours and a faster heart rate at night. The electrocardiogram below documents the presence of atrial fibrillation during sleep.