Hypoxia, Not the Frequency of Sleep Apnea, Causes Acute Hemodynamic Stress in Patients with Congestive Heart Failure

Abstract

Sleep apnea is strongly associated with HF, & could worsen HF through sympathetic activity, hypoxia, & hemodynamic & oxidative stress. If apneic activity causes acute stress in HF, it should increase BNP. We hypothesized that BNP changes are associated with the frequency & severity of apneic episodes, intermittent arousals, & hypoxia. 64 NYHA class II-III HF pts with EF <40% underwent a baseline sleep study. 5 pts with no sleep apnea & 12 with severe sleep apnea underwent repeat studies, during which blood was collected every 20 minutes to measure BNP.