Past research has identified sleep apnea as a risk factor for atrial fibrillation, but how common is sleep apnea in atrial fibrillation patients? In a recent study, 185 atrial fibrillation patients completed sleep apnea testing and 93% tested positive for the condition— 52.3% primary sleep apnea, 44.8% mixed apnea, and 2.9% pure central apnea. Because managing sleep apnea can slow atrial fibrillation progression, the finding suggests screening atrial fibrillation patients for the sleep disorder. American Journal of Cardiology, November 2022