Both central and obstructive sleep apnea are considered as independent risk factors of worsened prognosis in patients with heart failure with reduced ejection fraction (HFrEF). However, there is no evidence from randomized trials yet providing evidence that sleep apnea is an independent risk factor leading to an increase in cardiovascular mortality, including increased risk of sudden cardiac arrhythmic death in patients with ischemic cardiomyopathy. There are also no data from randomized trials assessing if treatment of sleep apnea by positive airway pressure therapy may improve cardiovascular outcomes in these patients, including reduced risk of sudden cardiac death.