Anecdotal recognition of the relationship between sleep apnea and atrial fibrillation has recently given way to more rigorous observational data. The risk of recurrence after atrial fibrillation interventions has also been studied longitudinally. There are numerous pathophysiological mechanisms that may link sleep apnea to atrial fibrillation. One of the most important mechanisms may be the significant changes, both acute and chronic, in autonomic tone that occur with obstructive apneas. Most observational data suggest that the success rates of atrial fibrillation interventions, such as cardioversions and ablation, are significantly improved for patients whose sleep apnea is treated. Epidemiological studies suggest that sleep apnea is a risk factor for new-onset atrial fibrillation, and that its presence reflects a poorer prognosis after atrial fibrillation interventions. Randomized controlled trials are necessary to clarify the effects of sleep apnea therapy on atrial fibrillation outcomes in individuals and communities.

This chapter outlines some characteristics of vascular dementia (VaD) related to large-vessel diseases in terms of pathology, pathogenesis, and clinical aspects. Large-vessel VaD is characterized by a step-wise cognitive deterioration, focal signs and symptoms which are the result of repeated ischemic strokes. The chapter reviews some of large-vessel diseases such as atherosclerosis, arterial dissection, angiitis, moyamoya disease, and intracranial arterial dolichoectasia. The pathogenesis of large-vessel VaD is complex and to some extent remains a matter of investigation. Efforts in defining diagnostic criteria are made in order to characterize patterns of brain infarction from which it is reliable to deduce the presence of dementia. Some of the most important pathophysiological mechanisms and factors implicated in large-vessel VaD are volume of lesions, number of lesions, location of lesions, and coexistence of other brain pathologies, particularly Alzheimer's disease (AD).