Changes in Cardiac Autonomic Control During Nocturnal Repetitive Oxygen Desaturation Episodes in Patients with Coronary Artery Disease

Background Periodic fluctuations in respiration such as Cheyne-Stokes respiration or the sleep apnoea syndrome are known to be associated with very-low-frequency oscillations in heart rate (cycle times about 30–120 s), which may be related to periodic changes in sympathetic and vagal tone. Since disturbances in cardiac sympathovagal balance have been associated with increased cardiovascular morbidity and mortality, especially in patients with coronary artery disease (CAD), we investigated changes in cardiac autonomic control in patients with CAD during periodic breathing espisodes. Methods Thirty-five patients with a left ventricular ejection fraction (LVEF) of > 50% and 13 patients with an LVEF of 50% and in nine patients with an LVEF of