ABC | Volume 110, Nº1, January 2018

Viewpoint Cognitive Deficit in Heart Failure and the Benefits of Aerobic Physical Activity Maria Luíza de Medeiros Rêgo, Daniel Aranha Rego Cabral, Eduardo Bodnariuc Fontes Universidade Federal do Rio Grande do Norte (UFRN); NeuroEx, Natal, RN – Brazil Mailing Address: Maria Luíza de Medeiros Rêgo • Rua Raimundo Chaves, 1652, F5. Postal Code 59064-390, Candelária, Natal, RN – Brazil E-mail: marialuizamedeirosr@gmail.com, eduardobfontes@gmail.com Manuscript received June 17, 2017, revised manuscript August 30, 2017, accepted September 25, 2017 Keywords Heart Failure; Indicators of Morbidity and Mortality; Cognition; Exercise. DOI: 10.5935/abc.20180002 Abstract Heart Failure is a clinical syndrome prevalent throughout the world and a major contribution to mortality of cardiac patients in Brazil. In addition, this pathology is strongly related to cerebral dysfunction, with a high prevalence of cognitive impairment. Many mechanisms may be related to cognitive loss, such as cerebral hypoperfusion, atrophy and loss of gray matter of the brain, and dysfunction of the autonomic nervous system. The literature is clear regarding the benefits of aerobic physical activity in healthy populations in the modulation of the autonomic nervous system and in brain functions. Studies have shown that in the population of patients with heart failure, exercise is associated with an improvement in cognitive function, as well as in cardiac autonomic regulation. However, little emphasis has been given to the mechanisms by which aerobic physical activity can benefit brain functioning, the autonomic nervous system and result in better cognitive performance, particularly in patients with heart failure. Therefore, the present work presents the ways in which brain areas responsible for cognition also act in the modulation of the autonomic nervous system, and emphasizes its importance for the understanding of cognitive impairment in relation to the pathophysiology of heart failure. It is also described the way in which aerobic physical activity can promote benefits when it is integrated into the therapy, associated to a better prognosis of the clinical picture of these patients. Heart Failure (HF) accounts for about 50% of all hospitalizations occurring in South America 1 and is one of the most frequent causes of hospitalization for cardiovascular diseases. 2 In addition to the direct influence on cardiac autonomic control, HF is strongly related to the presence of cerebral dysfunction and cognitive impairment, affecting approximately 75% of this population. 3 This cognitive deficit is associated with executive functions, including difficulties in the planning and execution of actions, low ability to solve problems and inhibit behaviors. 4 In practice, this results into less ability to perform daily activities such as shopping, feeding and locomotion - including walking - in addition to being related to lower self-care levels, higher hospitalization rates, increased expenses with more frequent hospitalizations, and, finally, there is an increase in morbidity and mortality in this pathology. In this sense, several treatments are performed in order to mitigate the deleterious effects caused by HF. However, such treatments usually involve invasive and / or medicamentous procedures such as heart transplantation, left ventricular assist device, beta-blockers, aldosterone antagonists, and angiotensin converting enzyme inhibitors. All these drugs, despite having proven beneficial results, can develop several types of side effects such as renal failure and hyperpotassemia. 2 In this sense, physical exercise has been pointed out as an important auxiliary tool in the treatment of patients with HF, however, little has been analyzed about its benefits to brain function. In the present work, the pathways by which the prefrontal cortex (PFC) is closely linked to the regulation of cardiac autonomic control and its influence on cognitive impairment in HF patients are presented. In addition, it is described how the regular practice of physical activity can promote benefits to brain function and cognitive performance in this population, as well as the contribution on cardiac autonomic control already widely described. In the search for the genesis of this problem, many mechanisms may be related to cognitive loss, such as cerebral hypoperfusion, atrophy and loss of gray matter of the brain, as well as autonomic nervous system (ANS) dysfunction. 5 A neuroimaging study in FC II patients found that individuals with this syndrome had impairment in several brain areas such as the hippocampus (short-term memory conversion in long-term memory), caudate nucleus (modulation of body movements), PFC (executive functions: decision‑making, planning , inhibitory control) and hypothalamus, fundamental areas in cognitive processes and autonomic control. 5 In this perspective, it is worth mentioning the existence of a recent pathophysiological model of cognitive decline in this population, which states that a set of factors such as hypoperfusion, hypoxia, inflammatory cytokines increase, thromboembolic diseases and hemodynamic abnormalities can lead to brain mass atrophy, generating cognitive deficits. 6 Another important point to emphasize about the pathophysiology imposed by HF is the severe dysfunction in ANS, characterized by increased sympathetic tone and decreased parasympathetic 7 and may be related to vasoconstriction. 8 As a consequence of this autonomic balance with sympathetic overlap, there is difficulty in the arrival of blood in various systems of the body, including the brain. Cerebral hypoperfusion in patients with HF may lead to reduced functional capacity 9 and cognitive deficits. 5 More specifically, permanent impairment of cerebral perfusion and chronic ischemia in deep areas may result in cognitive impairment and difficulty performing 91