ANA MARIA FONSECA WANDERLEY BRAGA

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Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina - Médico

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Assunto: muscle sympathetic nerve activity ×

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  • article 17 Citação(ões) na Scopus
    Obstructive Sleep Apnea Impairs Postexercise Sympathovagal Balance in Patients with Metabolic Syndrome
    (2015) CEPEDA, Felipe X.; TOSCHI-DIAS, Edgar; MAKI-NUNES, Cristiane; RONDON, Maria Urbana P. B.; ALVES, Maria Janieire N. N.; BRAGA, Ana Maria F. W.; MARTINEZ, Daniel G.; DRAGER, Luciano F.; LORENZI-FILHO, Geraldo; NEGRAO, Carlos E.; TROMBETTA, Ivani C.
    Study Objectives: The attenuation of heart rate recovery after maximal exercise (Delta HRR) is independently impaired by obstructive sleep apnea (OSA) and metabolic syndrome (MetS). Therefore, we tested the hypotheses: (1) MetS + OSA restrains Delta HRR; and (2) Sympathetic hyperactivation is involved in this impairment. Design: Cross-sectional study. Participants: We studied 60 outpatients in whom MetS had been newly diagnosed (ATP III), divided according to apnea-hypopnea index (AHI) >= 15 events/h in MetS + OSA (n = 30, 49 +/- 1.7 y) and AHI < 15 events/h in MetS - OSA (n = 30, 46 +/- 1.4 y). Normal age-matched healthy control subjects (C) without MetS and OSA were also enrolled (n = 16, 46 +/- 1.7 y). Interventions: Polysomnography, microneurography, cardiopulmonary exercise test. Measurements and Results: We evaluated OSA (AHI - polysomnography), muscle sympathetic nerve activity (MSNA - microneurography) and cardiac autonomic activity (LF = low frequency, HF = high frequency, LF/HF = sympathovagal balance) based on spectral analysis of heart rate (HR) variability. Delta HRR was calculated (peak HR minus HR at first, second, and fourth minute of recovery) after cardiopulmonary exercise test. MetS + OSA had higher MSNA and LF, and lower HF than MetS - OSA and C. Similar impairment occurred in MetS - OSA versus C (interaction, P < 0.01). MetS + OSA had attenuated Delta HRR at first, second, and at fourth minute than did C, and attenuated Delta HRR at fourth minute than did MetS - OSA (interaction, P < 0.001). Compared with C, MetS - OSA had attenuated Delta HRR at second and fourth min (interaction, P < 0.001). Further analysis showed association of the Delta HRR (first, second, and fourth minute) and AHI, MSNA, LF and HF components (P < 0.05 for all associations). Conclusions: The attenuation of heart rate recovery after maximal exercise is impaired to a greater degree where metabolic syndrome (MetS) is associated with moderate to severe obstructive sleep apnea (OSA) than by MetS with no or mild or no OSA. This is at least partly explained by sympathetic hyperactivity.
  • article
    Exaggerated Exercise Blood Pressure as a Marker of Baroreflex Dysfunction in Normotensive Metabolic Syndrome Patients
    (2021) DUTRA-MARQUES, Akothirene C.; RODRIGUES, Sara; CEPEDA, Felipe X.; TOSCHI-DIAS, Edgar; RONDON, Eduardo; CARVALHO, Jefferson C.; ALVES, Maria Janieire N. N.; BRAGA, Ana Maria F. W.; RONDON, Maria Urbana P. B.; TROMBETTA, Ivani C.
    Introduction Exaggerated blood pressure response to exercise (EEBP = SBP >= 190 mmHg for women and >= 210 mmHg for men) during cardiopulmonary exercise test (CPET) is a predictor of cardiovascular risk. Sympathetic hyperactivation and decreased baroreflex sensitivity (BRS) seem to be involved in the progression of metabolic syndrome (MetS) to cardiovascular disease. Objective To test the hypotheses: (1) MetS patients within normal clinical blood pressure (BP) may present EEBP response to maximal exercise and (2) increased muscle sympathetic nerve activity (MSNA) and reduced BRS are associated with this impairment. Methods We selected MetS (ATP III) patients with normal BP (MetS_NT, n = 27, 59.3% males, 46.1 +/- 7.2 years) and a control group without MetS (C, n = 19, 48.4 +/- 7.4 years). We evaluated BRS for increases (BRS+) and decreases (BRS-) in spontaneous BP and HR fluctuations, MSNA (microneurography), BP from ambulatory blood pressure monitoring (ABPM), and auscultatory BP during CPET. Results Normotensive MetS (MetS_NT) had higher body mass index and impairment in all MetS risk factors when compared to the C group. MetS_NT had higher peak systolic BP (SBP) (195 +/- 17 vs. 177 +/- 24 mmHg, P = 0.007) and diastolic BP (91 +/- 11 vs. 79 +/- 10 mmHg, P = 0.001) during CPET than C. Additionally, we found that MetS patients with normal BP had lower spontaneous BRS- (9.6 +/- 3.3 vs. 12.2 +/- 4.9 ms/mmHg, P = 0.044) and higher levels of MSNA (29 +/- 6 vs. 18 +/- 4 bursts/min, P < 0.001) compared to C. Interestingly, 10 out of 27 MetS_NT (37%) showed EEBP (MetS_NT+), whereas 2 out of 19 C (10.5%) presented (P = 0.044). The subgroup of MetS_NT with EEBP (MetS_NT+, n = 10) had similar MSNA (P = 0.437), but lower BRS+ (P = 0.039) and BRS- (P = 0.039) compared with the subgroup without EEBP (MetS_NT-, n = 17). Either office BP or BP from ABPM was similar between subgroups MetS_NT+ and MetS_NT-, regardless of EEBP response. In the MetS_NT+ subgroup, there was an association of peak SBP with BRS- (R = -0.70; P = 0.02), triglycerides with peak SBP during CPET (R = 0.66; P = 0.039), and of triglycerides with BRS- (R = 0.71; P = 0.022). Conclusion Normotensive MetS patients already presented higher peak systolic and diastolic BP during maximal exercise, in addition to sympathetic hyperactivation and decreased baroreflex sensitivity. The EEBP in MetS_NT with apparent well-controlled BP may indicate a potential depressed neural baroreflex function, predisposing these patients to increased cardiovascular risk.
  • article 42 Citação(ões) na Scopus
    Exercise training improves neurovascular control and functional capacity in heart failure patients regardless of age
    (2012) ANTUNES-CORREA, Ligia M.; KANAMURA, Bianca Y.; MELO, Ruth C.; NOBRE, Thais S.; UENO, Linda M.; FRANCO, Fabio G. M.; ROVEDA, Fabiana; BRAGA, Ana Maria; RONDON, Maria U. P. B.; BRUM, Patricia C.; BARRETTO, Antonio C. P.; MIDDLEKAUFF, Holly R.; NEGRAO, Carlos E.
    Background: Exercise training is a non-pharmacological strategy for treatment of heart failure. Exercise training improves functional capacity and quality of life in patients. Moreover, exercise training reduces muscle sympathetic nerve activity (MSNA) and peripheral vasoconstriction. However, most of these studies have been conducted in middle-aged patients. Thus, the effects of exercise training in older patients are much less understood. The present study was undertaken to investigate whether exercise training improves functional capacity, muscular sympathetic activation and muscular blood flow in older heart failure patients, as it does in middle-aged heart failure patients. Design: Fifty-two consecutive outpatients with heart failure from the database of the Unit of Cardiovascular Rehabilitation and Physiology Exercise were divided by age (middle-aged, defined as 45-59 years, and older, defined as 60-75 years) and exercise status (trained and untrained). Methods: MSNA was recorded directly from the peroneal nerve using the microneurography technique. Forearm Blood Flow (FBF) was measured by venous occlusion plethysmography. Functional capacity was evaluated by cardiopulmonary exercise test. Results: Exercise training significantly and similarly increased FBF and peak VO2 in middle-aged and older heart failure patients. In addition, exercise training significantly and similarly reduced MSNA and forearm vascular resistance in these patients. No significant changes were found in untrained patients. Conclusion: Exercise training improves neurovascular control and functional capacity in heart failure patients regardless of age.