Detecção de disfunção autonômica em pacientes em hemodiálise utilizando o teste ergométrico

Disfunção autonômica (DA) está frequentemente presente em pacientes em programa de hemodiálise (HD) e tem sido associada ao maior risco de mortalidade cardiovascular nesta população. O comportamento da frequência cardíaca (FC) no teste ergométrico (TE) tem sido utilizado na avaliação da função autonômica. Objetivos. Estabelecer a frequência de alterações autonômicas durante o TE em pacientes em HD em comparação a um grupo controle e correlacionar os resultados com a variabilidade da FC (VFC) ao Holter e com a presença de microinflamação. Métodos. Estudo transversal comparativo em hemodialisados e um grupo controle pareado por gênero e idade sem doença renal declarada. O protocolo consistiu de: avaliação clínica, coleta de sangue, ecocardiograma, TE e Holter. O TE foi realizado em esteira pelo protocolo de rampa, sintoma-limitado, com recuperação ativa e determinação de VFC ao esforço e recuperação. Resultados. Um total de 41 hemodialisados e 41 controles concluiu o estudo. O grupo HD apresentou maiores níveis de proteína C-reativa (PCR) (1,02±1,20 vs. 0,47±0,007 mg/dL; p=0,010) e maior beta 2-microglobulina, beta2, (27,9±8,1 vs. 1,5±0,5 mg/dL; p<0,001) do que controles. Os parâmetros mais discriminativos ao TE foram (HD vs. controle, média ± DP): índice cronotrópico (IC) 57,5±19,1 vs. 89,1±12,1%, p<0,001; FC recuperação (FCR) 1ºmin 11,9±9,1 vs. 19,4±8,6bpm, p<0,001; FCR 2ºmin 21,3±12,3 vs. 33,9±10,5bpm, p< 0,001; FCR 3ºmin 33,8±21,3 vs. 53,3±18,0bpm, p<0,001; FCR 4º min 38,3±21,9 vs. 58,0±15,7bpm, p<0,001; FCR 5ºmin 40,8±21,3 vs. 60,3±14,4bpm, p<0,001; índice FC/FCR 0,80±0,19 vs. 0,69±0,18, p=0,008; QTc pico 419,5±22,2 vs. 403,8±21,6ms, p=0,006; SDNN exercício 33,7 ± 14,2 vs. 50,0 ± 21,8ms, p<0,001; e SDNN recuperação 20,1±9,8 vs. 27,3±17,4ms, p=0,024. A frequência de parâmetros anormais ao TE foi (HD vs. controle, %): IC 80,54 vs. 12,2, OR=29,7 (p<0,001); FCR 1ºmin 56,1 vs. 7,3, OR=17,1 (p<0,001); FCR 2ºmin 56,1 vs. 12,2, OR=9,7 (p<0,001); índice FC/FCR 85,4 vs. 53,7, OR=2,6 (p=0,045); e SDNN exercício 89,5 vs. 56,1, OR=6,7 (p=0,002). Os parâmetros IC, FCR 1ºmin e SDNN exercício foram usados para compor um escore no qual 83% dos pacientes em HD teve 2 ou 3 testes anormais enquanto 81% dos controles teve 0 ou 1. HD foi independentemente associada com IC e escore de DA ≥2 em todos os modelos de regressão logística testados. Houve correlação entre os seguintes parâmetros do TE e a VFC ao Holter: IC, FCR 2ºmin, índice FC/FCR, SDNN exercício e rMSSD recuperação. A PCR se correlacionou com: FCR 1ºmin, FCR 2ºmin, índice FC/FCR e SDNN exercício; a beta2, com a FCR 4ºmin e FCR 5ºmin. Conclusão. O TE foi seguro e útil para diagnosticar a DA em pacientes em HD identificando casos positivos com maior frequência do que os outros testes estudados. A associação com o Holter e a inflamação sugere que as alterações encontradas podem de fato refletir DAAutonomic dysfunction (AD) is highly prevalent in renal patients undergoing hemodialysis (HD) and has been implicated in the increased risk of cardiovascular mortality in this setting. Changes in heart rate (HR) in the exercise treadmill test (ETT) have been used to assess AD. Objectives. To assess the frequency of HR related AD during an ETT in HD patients in comparison to a control group and to correlate the results with the HR variability (HRV) at 24h-Holter, and with the presence of microinflammation. Methods. Cross-sectional study with HD patients and a control group matched by gender and age without overt kidney disease. The study protocol consisted of: clinical examination, blood collection, echocardiogram, 24-h Holter, and ETT. The ETT was performed in ramp treadmill protocol, and was symptom-limited with active recovery. HRV was assessed in exercise and recovery during ETT. Results. Forty-one HD patients and 41 controls concluded the study. HD group had higher levels of C-reactive protein (CRP) than controls (1.02±1.20 vs. 0.47±0.007 mg/dL, p=0.010) and higher beta 2-microglobulin, beta2, (27.9±8.1 vs. 1.5±0.5 mg/dL, p<0.001). The most discriminating parameters in ETT were (HD patients vs. control, mean±SD): chronotropic index (CI) 57.5±19.1 vs. 89.1±12.1%, p<0.001; HR recovery (HRR) 1stmin 11.9±9.1 vs. 19.4±8.6bpm, p<0.001; HRR 2ndmin 21.3±12.3 vs. 33.9±10.5bpm, p<0.001; HRR 3rdmin 33.8±21.3 vs. 53.3±18.0bpm, p<0.001; HRR 4thmin 38.3±21.9 vs. 58.0±15.7bpm, p<0.001; HRR 5thmin 40.8±21.3 vs. 60.3±14.4bpm, p<0.001; HR/HRR index 0.80±0.19 vs. 0.69± 0.18, p=0.008; QTc peak 419.5±22.2 vs. 403.8±21.6 msec, p=0.006; SDNN exercise 33.7 ± 14.2 vs. 50.0 ± 21.8msec, p <0.001; and SDNN recovery 20.1±9.8 vs. 27.3±17.4msec, p=0.024. The frequency of abnormal autonomic parameters in ETT was (HD vs. control, %): CI 80.54 vs. 12.2, OR=29.7 (p<0.001); HRR 1stmin 56.1 vs. 7.3, OR=17.1 (p<0.001); HRR 2ndmin 56.1 vs. 12.2, OR=9.7 (p<0.001); HR/HRR index 85.4 vs. 53.7, OR=2.6 (p=0.045); and SDNN exercise 89.5 vs. 56.1, OR=6.7 (p=0.002). The parameters CI, HRR 1stmin, and SDNN exercise were used to compose a score in which 83% of HD patients had 2 or 3 abnormal tests and 81% of controls had 0 or 1. HD was independently associated with CI and score AD in all logistic regression models tested. There was correlation between the following ETT autonomic parameters and HR variability by 24-h Holter: CI, HRR 2ndmin, RHR/HRR index, SDNN exercise and rMSSD recovery. CRP correlated with HRR 2ndmin, RHR/HRR index and SDNN exercise; beta2, with HRR 4thmin and HRR 5thmin. There was no correlation between CRP and beta2 with any parameter assessing HRV on the 24-h Holter. Conclusion. The ETT was feasible and useful to diagnose AD in HD patients and identified a higher number of positive cases than the other studied tests. Findings at ETT correlated with the HRV at the 24h-Holter and microinflammation suggesting that findings can indeed reflect true AD131f

Carreira et al Blood pressure response to maximum stress Response of Blood Pressure to Maximum Exercise in Hypertensive Patients under Different Therapeutic Programs Original Article

Objective -To evaluate the behavior of blood pressure during exercise in patients with hypertension controlled by frontline antihypertension drugs. Methods

Response of blood pressure to maximum exercise in hypertensive patients under different therapeutic programs

OBJECTIVE: To evaluate the behavior of blood pressure during exercise in patients with hypertension controlled by frontline antihypertension drugs. METHODS: From 979ergometric tests we retrospectively selected 49 hipertensive patients (19 males). The age was 53±12 years old and normal range rest arterial pressure (<=140/90 mmHg) all on pharmacological monotherapy. There were 12 on beta blockers; 14 on calcium antagonists, 13 on diuretics and 10 on angiotensin converting enzyme inhibitor. Abnormal exercise behhavior of blood pressure was diagnosed if anyone of the following criteria was detected: peak systolic pressure above 220 mmHg, raising of systolic pressure > or = 10 mmHg/MET; or increase of diastolic pressure greater than 15 mmHg. RESULTS: Physiologic response of arterial blood pressure occurred in 50% of patients on beta blockers, the best one (p<0.05), in 36% and 31% on calcium antagonists and on diuretics, respectively, and in 20% on angiotensin converting enzyme inhibitor, the later the leastr one (p<0.05). CONCLUSION: Beta-blockers were more effective than calcium antagonists, diuretics and angiotensin-converting enzyme inhibitors in controlling blood pressure during exercise, and angiotensin converting enzyme inhibitors the least effective drugs

Heart Rate Variability Correlates to Functional Aerobic Impairment in Hemodialysis Patients

Background:Autonomic dysfunction (AD) is highly prevalent in hemodialysis (HD) patients and has been implicated in their increased risk of cardiovascular mortality.Objective:To correlate heart rate variability (HRV) during exercise treadmill test (ETT) with the values obtained when measuring functional aerobic impairment (FAI) in HD patients and controls.Methods:Cross-sectional study involving HD patients and a control group. Clinical examination, blood sampling, transthoracic echocardiogram, 24-hour Holter, and ETT were performed. A symptom-limited ramp treadmill protocol with active recovery was employed. Heart rate variability was evaluated in time domain at exercise and recovery periods.Results:Forty-one HD patients and 41 controls concluded the study. HD patients had higher FAI and lower HRV than controls (p<0.001 for both). A correlation was found between exercise HRV (SDNN) and FAI in both groups. This association was independent of age, sex, smoking, body mass index, diabetes, and clonidine or beta-blocker use, but not of hemoglobin levels.Conclusion:No association was found between FAI and HRV on 24-hour Holter or at the recovery period of ETT. Of note, exercise HRV was inversely correlated with FAI in HD patients and controls. (Arq Bras Cardiol. 2015; [online]. ahead print, PP.0-0