Função cardíaca, modulação autonômica cardiovascular, oxigenação e complacência cerebral no diabetes mellitus tipo 2 com e sem neuropatia autonômica cardiovascular

Abstract

Cardiovascular autonomic neuropathy (CAN) is a type 2 diabetes mellitus (T2DM) complication, marked by changes in the sympathetic and parasympathetic autonomic nervous system leading to high mortality. The degree of dynamic heart rate oscillations involvement with baroreflex control and cardiac function in the absence and presence of CAN is still scarce. Furthermore, the influence of CAN on cerebral and peripheral oxygenation, intracranial compliance and the relationship with cardiac function remain unknown. Thus, this thesis consisted of a systematic review and three cross-sectional studies, with the aim of elucidating aspects of the influence of diabetes with and without CAN on heart rate fragmentation (HRF) and its relationship with cardiovascular autonomic modulation and cardiac function. Furthermore, to explore oxygenation and intracranial compliance responses in CAN and cardiometabolic diseases in the face of physiological stressors (cardiopulmonary testing and active postural change, APC). The study I, entitled: “Heart rate fragmentation is impaired in patients with type 2 diabetes mellitus” retrospectively evaluated whether T2DM without CAN increase the HRF and what is the relationship with classical heart rate variability (HRV) indices. The results suggest that T2DM subjects without CAN have increased HRF compared to healthy controls. Furthermore, the HRF was complementary to the HRV indices. The study II, entitled: “Heart rate fragmentation and its relationship with cardiovascular autonomic modulation and cardiac function in type 2 diabetes with cardiovascular autonomic neuropathy”, evaluated whether CAN increase the HRF and what is the relationship with the cardiovascular autonomic modulation indices and the cardiac function. CAN increased the degree of HRF at rest, and the HRF indices allow obtaining complementary information to the indices of cardiovascular autonomic modulation and the left ventricular systolic function. The study III, entitled: “Cerebral oxygenation during cardiopulmonary exercise testing in cardiorespiratory disease: a systematic review,” summarized the acute cerebral oxygenation response during cardiopulmonary exercise testing (CPET) in cardiovascular, metabolic, and respiratory disease. During CPET, individuals with cardiovascular disease had reduced cerebral oxygenation and individuals with obstructive sleep apnea extracted less cerebral oxygen. A patter for metabolic diseases has not been established. The study IV, entitled: “Oxygenation and intracranial compliance and their relationship to cardiac function in type 2 diabetes with and without cardiovascular autonomic neuropathy”, investigated whether CAN reduce oxygenation and compliance after APC and the relationship of cardiac function to this response. CAN reduce cerebral oxygen extraction and increase intracranial compliance in orthostatism. Also, relationships between lower diastolic function and inadequate glycemic control indicate a reduction in oxygen extraction and intracranial compliance in type 2 diabetes, baroreflex control, left ventricular systolic and diastolic function and responses of oxygenation and intracranial compliance. This reinforces the importance of early monitoring of individuals with T2DM in the disease progress.