Central sleep apnea.

CSA is a heterogeneous disorder with numerous causes and associations. It is much more common than previously believed, and is easily overlooked if not carefully sought. If undiagnosed, it may be associated with significant morbidity and even mortality. It is easily and noninvasively diagnosed, and therapy is often effective and can favorably impact the course of disease. Consequently, it would behoove all physicians to at least consider the diagnosis of CSA in any patient who has any predisposing condition, sign or symptom associated with this disease entity.