However, some patients are contraindications for NIV, with Loss of consciousness, hemodynamic instability, and some are intolerance due to dryness, gastric distension, skin breakdown and noise, with complaints of insomnia and sleep disturbance. The aforementioned factors largely limits its use. Recently, the heated humidified high-flow nasal cannula (HFNC), free of psychic stress and physical discomfort, shows a favorable compliance and tolerance in treating the hypoxemic patients. As a result, in this comfortable setting we predict a high sleep quality in HFNC oxygen therapy. Evidence has suggested that sleep abnormalities trigger the cascaded release of C-reactive protein (CRP). As is well known that CRP is involved in atrial structural remodeling and asynchronous conduction, which attribute to the initiation and maintenance of AF.