Metaboreflex activation delays heart rate recovery after aerobic exercise in never-treated hypertensive men.

KEY POINTS: Recent evidence indicates that metaboreflex regulates heart rate recovery after exercise (HRR). An increased metaboreflex activity during the post-exercise period might help to explain the reduced HRR observed in hypertensive subjects. Using lower limb circulatory occlusion, the present study showed that metaboreflex activation during the post-exercise period delayed HRR in never-treated hypertensive men compared to normotensives. These findings may be relevant for understanding the physiological mechanisms associated with autonomic dysfunction in hypertensive men. ABSTRACT: Muscle metaboreflex influences heart rate (HR) regulation after aerobic exercise. Therefore, increased metaboreflex sensitivity may help to explain the delayed HR recovery (HRR) reported in hypertension. The present study assessed and compared the effect of metaboreflex activation after exercise on HRR, cardiac baroreflex sensitivity (cBRS) and heart rate variability (HRV) in normotensive (NT) and hypertensive (HT) men. Twenty-three never-treated HT and 25 NT men randomly underwent two-cycle ergometer exercise sessions (30 min, 70% V̇O2 peak ) followed by 5 min of inactive recovery performed with (occlusion) or without (control) leg circulatory occlusion (bilateral thigh cuffs inflated to a suprasystolic pressure). HRR was assessed via HR reduction after 30, 60 and 300 s of recovery (HRR30s, HRR60s and HRR300s), as well as by the analysis of short- and long-term time constants of HRR. cBRS was assessed by sequence technique and HRV by the root mean square residual and the root mean square of successive differences between adjacent RR intervals on subsequent 30 s segments. Data were analysed using two- and three-way ANOVA. HRR60s and cBRS were significant and similarly reduced in both groups in the occlusion compared to the control session (combined values: 20 ± 10 vs. 26 ± 9 beats min-1 and 2.1 ± 1.2 vs. 3.2 ± 2.4 ms mmHg-1 , respectively, P < 0.05). HRR300s and HRV were also reduced in the occlusion session, although these reductions were significantly greater in HT compared to NT (-16 ± 11 vs. -8 ± 15 beats min-1 for HRR300s, P < 0.05). The results support the role of metaboreflex in HRR and suggest that increased metaboreflex sensitivity may partially explain the delayed HRR observed in HT men.

Can blood pressure decrease after maximal exercise test predict the blood pressure lowering effect of aerobic training in treated hypertensive men?

The acute decrease in blood pressure (BP) observed after a session of exercise (called post-exercise hypotension) has been proposed as a tool to predict the chronic reduction in BP induced by aerobic training. Therefore, this study investigated whether post-exercise hypotension observed after a maximal exercise test is associated to the BP-lowering effect of aerobic training in treated hypertensives. Thirty hypertensive men (50 ± 8 years) who were under consistent anti-hypertensive treatment underwent a maximal exercise test (15 watts/min until exhaustion), and post-exercise hypotension was determined by the difference between BP measured before and at 30 min after the test. Subsequently, the patients underwent 10 weeks of aerobic training (3 times/week, 45 min/session at moderate intensity), and the BP-lowering effect of training was assessed by the difference in BP measured before and after the training period. Pearson correlations were employed to evaluate the associations. Post-maximal exercise test hypotension was observed for systolic and mean BPs (-8 ± 6 and -2 ± 4 mmHg, all P < 0.05). Aerobic training reduced clinic systolic/diastolic BPs (-5 ± 6/-2 ± 3 mmHg, both P < 0.05) as well as awake and 24 h mean BPs (-2 ± 6 and -2 ± 5 mmHg, all P < 0.05). No significant correlation was detected between post-exercise hypotension and the BP-lowering effect of training either for clinic or ambulatory BPs (r values ranging from 0.00 to 0.32, all p > 0.05). Post-exercise hypotension assessed 30 min after a maximal exercise test cannot be used to predict the BP-lowering effect of aerobic training in treated hypertensive men.

Post-concurrent exercise hemodynamics and cardiac autonomic modulation.

Concurrent training is recommended for health improvement, but its acute effects on cardiovascular function are not well established. This study analyzed hemodynamics and autonomic modulation after a single session of aerobic (A), resistance (R), and concurrent (A + R) exercises. Twenty healthy subjects randomly underwent four sessions: control (C:30 min of rest), aerobic (A:30 min, cycle ergometer, 75% of VO(2) peak), resistance (R:6 exercises, 3 sets, 20 repetitions, 50% of 1 RM), and concurrent (AR: A + R). Before and after the interventions, blood pressure (BP), heart rate (HR), cardiac output (CO), and HR variability were measured. Systolic BP decreased after all the exercises, and the greatest decreases were observed after the A and AR sessions (-13 ± 1 and -11 ± 1 mmHg, respectively, P < 0.05). Diastolic BP decreased similarly after all the exercises, and this decrease lasted longer after the A session. CO also decreased similarly after the exercises, while systemic vascular resistance increased after the R and AR sessions in the recovery period (+4.0 ± 1.7 and +6.3 ± 1.9 U, respectively, P < 0.05). Stroke volume decreased, while HR increased after the exercises, and the greatest responses were observed after the AR session (SV, A = -14.6 ± 3.6, R = -22.4 ± 3.5 and AR = -23.4 ± 2.4 ml; HR, A =+13 ± 2, R =+15 ± 2 vs. AR =+20 ± 2 bpm, P < 0.05). Cardiac sympathovagal balance increased after the exercises, and the greatest increase was observed after the AR session (A = +0.7 ± 0.8, R = +1.0 ± 0.8 vs. AR = +1.2 ± 0.8, P < 0.05). In conclusion, the association of aerobic and resistance exercises in the same training session did not potentiate post-exercise hypotension, and increased cardiac sympathetic activation during the recovery period.

Comparison of morning versus evening aerobic-exercise training on heart rate recovery in treated hypertensive men: a randomized controlled trial.

Heart rate recovery (HRR) is a marker of cardiac autonomic regulation and an independent predictor of mortality. Aerobic-exercise training conducted in the evening (evening training) produces greater improvement in resting cardiac autonomic control in hypertensives than morning training, suggesting it may also result in a faster autonomic restoration postexercise. This study compared the effects of morning training and evening training on HRR in treated hypertensive men. Forty-nine treated hypertensive men were randomly allocated into three groups: morning training, evening training and control. Training was conducted three times/week for 10 weeks. Training groups cycled (45 min, moderate intensity) while control group stretched (30 min). In the initial and final assessments of the study, HRR60s and HRR300s were evaluated during the active recovery (30 W) from cardiopulmonary exercise tests (CPET) conducted in the morning and evening. Between-within ANOVAs were applied (P ≤ 0.05). Only evening training increased HRR60s and HRR300 differently from control after morning CPET (+4 ± 5 and +7 ± 8 bpm, respectively, P < 0.05) and only evening training increased HRR300s differently from morning training and control after evening CPET (+8 ± 6 bpm, P < 0.05). Evening training improves HRR in treated hypertensive men, suggesting that this time of day is better for eliciting cardiac autonomic improvements via aerobic training in hypertensives.

Poor sleep quality is associated with cardiac autonomic dysfunction in treated hypertensive men.

Hypertensives present cardiac autonomic dysfunction. Reduction in sleep quality increases blood pressure (BP) and favors hypertension development. Previous studies suggested a relationship between cardiovascular autonomic dysfunction and sleep quality, but it is unclear whether this association is present in hypertensives. Thus, this study evaluated the relationship between sleep quality and cardiac autonomic modulation in hypertensives. Forty-seven middle-aged hypertensive men under consistent anti-hypertensive treatment were assessed for sleep quality by the Pittsburgh Sleep Quality Index (PSQI-higher score means worse sleep quality). Additionally, their beat-by-beat BP and heart rate (HR) were recorded, and cardiac autonomic modulation was assessed by their variabilities. Mann-Whitney and t tests were used to compare different sleep quality groups: poor (PSQI > 5, n = 24) vs good (PSQI ≤ 5, n = 23), and Spearman's correlations to investigate associations between sleep quality and autonomic markers. Patients with poor sleep quality presented lower cardiac parasympathetic modulation (HR high-frequency band = 26 ± 13 vs 36 ± 15 nu, P = .03; HR total variance = 951 ± 1373 vs 1608 ± 2272 ms2 , P = .05) and cardiac baroreflex sensitivity (4.5 ± 2.3 vs 7.1 ± 3.7 ms/mm Hg, P = .01). Additionally, sleep quality score presented significant positive correlation with HR (r = +0.34, P = .02) and negative correlations with HR high-frequency band (r = -0.34, P = .03), HR total variance (r = -0.35, P = .02), and cardiac baroreflex sensitivity (r = -0.42, P = .01), showing that poor sleep quality is associated with higher HR and lower cardiac parasympathetic modulation and baroreflex sensitivity. In conclusion, in treated hypertensive men, poor sleep quality is associated with cardiac autonomic dysfunction.

Effects of postexercise cooling on heart rate recovery in normotensive and hypertensive men.

BACKGROUND: Postexercise heart rate recovery (HRR) is determined by cardiac autonomic restoration after exercise and is reduced in hypertension. Postexercise cooling accelerates HRR in healthy subjects, but its effects in a population with cardiac autonomic dysfunction, such as hypertensives (HT), may be blunted. This study assessed and compared the effects of postexercise cooling on HRR and cardiac autonomic regulation in HT and normotensive (NT) subjects. METHODS: Twenty-three never-treated HT (43 ± 8 years) and 25 NT (45 ± 8 years) men randomly underwent two exercise sessions (30 min of cycling at 70% VO2peak ) followed by 15 min of recovery. In one randomly allocated session, a fan was turned on in front of the subject during the recovery (cooling), while in the other session, no cooling was performed (control). HRR was assessed by heart rate reductions after 60 s (HRR60s) and 300 s (HRR300s) of recovery, short-term time constant of HRR (T30) and the time constant of the HRR after exponential fitting (HRRτ). HRV was assessed using time- and frequency-domain indices. RESULTS: HRR and HRV responses in the cooling and control sessions were similar between the HT and NT. Thus, in both groups, postexercise cooling equally accelerated HRR (HRR300s = 39±12 versus 36 ± 10 bpm, P≤0·05) and increased postexercise HRV (lnRMSSD = 1·8 ± 0·7 versus 1·6 ± 0·7 ms, P≤0·05). CONCLUSION: Differently from the hypothesis, postexercise cooling produced similar improvements in HRR in HT and NT men, likely by an acceleration of cardiac parasympathetic reactivation and sympathetic withdrawal. These results suggest that postexercise cooling equally accelerates HRR in hypertensive and normotensive subjects.

Morning versus Evening Aerobic Training Effects on Blood Pressure in Treated Hypertension.

INTRODUCTION: The acute blood pressure (BP) decrease is greater after evening than morning exercise, suggesting that evening training (ET) may have a greater hypotensive effect. OBJECTIVE: This study aimed to compare the hypotensive effect of aerobic training performed in the morning versus evening in treated hypertensives. METHODS: Fifty treated hypertensive men were randomly allocated to three groups: morning training (MT), ET, and control (C). Training groups cycled for 45 min at moderate intensity (progressing from the heart rate of the anaerobic threshold to 10% below the heart rate of the respiratory compensation point), while C stretched for 30 min. Interventions were conducted 3 times per week for 10 wk. Clinic and ambulatory BP and hemodynamic and autonomic mechanisms were evaluated before and after the interventions. Clinic assessments were performed in the morning (7:00-9:00 AM) and evening (6:00-8:00 PM). Between-within ANOVA was used (P ≤ 0.05). RESULTS: Only ET decreased clinic systolic BP differently from C and MT (morning assessment -5 ± 6 mm Hg and evening assessment -8 ± 7 mm Hg, P < 0.05). Only ET reduced 24 h and asleep diastolic BP differently from C and MT (-3 ± 5 and -3 ± 4 mm Hg, respectively, P < 0.05). Systemic vascular resistance decreased from C only in ET (P = 0.03). Vasomotor sympathetic modulation decreased (P = 0.001) and baroreflex sensitivity (P < 0.02) increased from C in both training groups with greater changes in ET than MT. CONCLUSIONS: In treated hypertensive men, aerobic training performed in the evening decreased clinic and ambulatory BP due to reductions in systemic vascular resistance and vasomotor sympathetic modulation. Aerobic training conducted at both times of day increases baroreflex sensitivity, but with greater after ET.

[Evaluation of hypertensive retinopathy through the oscillatory potentials of the electroretinogram]. / Avaliação da retinopatia hipertensiva através do potencial oscilatório do eletrorretinograma.

PURPOSE: To evaluate the behavior of the scotopic Oscillatory Potentials (OP) of total field electroretinogram (ERG) in hypertensive retinopathy. METHODS: Forty-four patients (n=44) were submitted to clinical evaluation and subdivided in to 2 groups: hypertensives (HT) and normotensives (NT). The hypertensives patients were maintained under placebo during the period of the study. Soon afterwards, they were submitted to ophthalmological evaluation and accomplishment of ERG. Total field electroretinogram (ERG), with recording of the answers: scotopic, maximum scotopic, OP scotopic, photopic and flicker.For analysis of the OP answer the latency of the first 2 peaks and the average value of the width of the first 3 peaks of the compound of 3 consecutive answers, denominated Oscillatory Index (OI) were considered. RESULTS: The sample was composed of 44 patients, with a mean age of 51.55 +/- 7.2 range (34 to 68) years, 24 being females. Arterial hypertension affected 26 (59.1%) of the patients, while 18 (40.9%) were normotensives. The average of the obtained IO was 257.41 microv in the NT group and of 217.81 microv in HT (p=0.006). The averages of latencies obtained for peaks 1 (NT-18.42 and HT-17.91) and 2 (NT-24.54 and HT - 24.29) were not different between the groups (p>0.05). CONCLUSIONS: The hypertensive patients presented significantly smaller oscillatory index than the normotensives, suggesting that arterial hypertension might cause dysfunction of the internal retina.

Impact of body mass index on blood pressure levels in patients with polycystic ovary syndrome.

As there is controversy about the prevalence of hypertension in patients with polycystic ovary syndrome (PCOS) and, up to the present moment, no studies have evaluated the impact of body mass index (BMI) on blood pressure levels (BP) in these patients, we studied retrospectively sixty-nine patients with PCOS, with BMI of 29.0 +/- 6.7 kg/m(2) and aged 25.6 +/-5.6 yr, subdivided into three groups according to BMI (normal, overweight and obese) and evaluated regarding BP (mercury sphygmomanometer), basal hormonal profile, fasting glucose, and insulin sensitivity (HOMA-IR). Mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) were normal (118.1 +/- 17.0 and 74.7+/- 11.5 mmHg, respectively), with a hypertension prevalence of 20.3%. Of these patients, 78.6% were obese and 21.4% were overweight. When the groups were compared according to BMI, a significant increase in SBP and DBP was observed (higher in overweight and obese patients for SBP and higher in obese for DBP), as well as a significant progressive increase in glucose, insulin, homeostatic model assessment, and a significant progressive decline in LH levels. When the patients were subdivided as normotensive or hypertensive, a significant difference was observed only for BMI (28.2 +/- 6.1 and 34.7 +/- 8.6 kg/m(2), respectively; p = 0.007). In conclusion, we observed a significant and progressive impact of BMI on blood pressure levels in our patients with polycystic ovary syndrome.

Ambulatory Blood Pressure Monitoring: Five Decades of More Light and Less Shadows.

Casual blood pressure measurements have been extensively questioned over the last five decades. A significant percentage of patients have different blood pressure readings when examined in the office or outside it. For this reason, a change in the paradigm of the best manner to assess blood pressure has been observed. The method that has been most widely used is the Ambulatory Blood Pressure Monitoring - ABPM. The method allows recording blood pressure measures in 24 hours and evaluating various parameters such as mean BP, pressure loads, areas under the curve, variations between daytime and nighttime, pulse pressure variability etc. Blood pressure measurements obtained by ABPM are better correlated, for example, with the risks of hypertension. The main indications for ABPM are: suspected white coat hypertension and masked hypertension, evaluation of the efficacy of the antihypertensive therapy in 24 hours, and evaluation of symptoms. There is increasing evidence that the use of ABPM has contributed to the assessment of blood pressure behaviors, establishment of diagnoses, prognosis and the efficacy of antihypertensive therapy. There is no doubt that the study of 24-hour blood pressure behavior and its variations by ABPM has brought more light and less darkness to the field, which justifies the title of this review.

Significado clínico da hipertensão durante o sono / Clinical meaning of hypertension during sleep

A anormalidade da pressão arterial durante o período de sono identificada como médias ≥ 120 x 70 mm Hg, por meio de registros da Monitorização Ambulatorial da Pressão Arterial de 24 horas (MAPA), está relacionada a pior prognóstico e maior risco de eventos. Essa alteração pode ser decorrência de vários fatores, mas, geralmente, independentemente da causa está fortemente relacionada a maior probabilidade de eventos e mortalidade cardiovasculares. Ainda restam dúvidas, embora evidências começam a ser oferecidas, se o tratamento medicamentoso desse estado de comportamento peculiar da pressão arterial nas 24 horas deva ser instituído. Nessa revisão esses aspectos são amplamente discutidos com base nas melhores evidências disponíveis

The abnormality of blood pressure during the sleep period identified as means ≥ 120 x 70 mm Hg, through 24-hour Ambulatory Blood Pressure Monitoring (ABPM) records, is related to a worse prognosis and greater risk of events. This change can be due to several factors, but, generally, regardless of the cause, it is strongly related to a higher probability of cardiovascular events and mortality. Doubts remain, although evidence is beginning to be offered, whether drug treatment of this peculiar behavioral state of blood pressure within 24 hours should be instituted. In this review, these aspects are widely discussed based on the best available evidence

Equivalence of indapamide SR and enalapril on microalbuminuria reduction in hypertensive patients with type 2 diabetes: the NESTOR Study.

OBJECTIVES: To test whether microalbuminuria in patients with type 2 diabetes and hypertension is primarily dependent on the severity of hypertension, and to compare the effectiveness of two antihypertensive drugs with opposite effects on the renin-angiotensin system [the diuretic, indapamide sustained release (SR), and an angiotensin-converting enzyme inhibitor, enalapril] in reducing microalbuminuria. DESIGN: A multinational, multicentre, controlled, double-blind, double-dummy, randomized, two-parallel-groups study over 1 year. METHODS: After a 4-week placebo run-in period, 570 patients (ages 60.0 +/- 9.9 years, 64% men) with type 2 diabetes, essential hypertension [systolic blood pressure (SBP) 140-180 mmHg, and diastolic blood pressure (DBP) < 110 mmHg], and persistent microalbuminuria (20-200 microg/min) were allocated randomly to groups to receive indapamide SR 1.5 mg (n = 284) or enalapril 10 mg (n = 286) once a day. Amlodipine, atenolol, or both were added, if necessary, to achieve the target blood pressure of 140/85 mmHg. RESULTS: There was a significant reduction in the urinary albumin : creatinine ratio. Mean reductions were 35% [95% confidence interval (CI) 24 to 43] and 39% (95% CI 30 to 47%) in the indapamide SR and enalapril groups, respectively. Equivalence was demonstrated between the two groups [1.08 (95% CI 0.89 to 1.31%); P = 0.01]. The reductions in mean arterial pressure (MAP) were 16.6 +/- 9.0 mmHg for the indapamide SR group and 15.0 +/- 9.1 mmHg for the enalapril group (NS); the reduction in SBP was significantly greater (P = 0.0245 ) with indapamide SR. More than 50% of patients in each group required additional antihypertensive therapy, with no differences between groups. Both treatments were well tolerated. CONCLUSIONS: Indapamide-SR-based therapy is equivalent to enalapril-based therapy in reducing microalbuminuria with effective blood pressure reduction in patients with hypertension and type 2 diabetes.

[Comparison of the profiles of hypertensive patients seen at the emergency department and in ambulatory care]. / Comparação dos perfis dos pacientes hipertensos atendidos em Pronto-Socorro e em tratamento ambulatorial.

This study compares 100 hypertensive patients in emergency units with those who were seen in outpatient clinics. Hypertensive patients seen at the emergency unit showed to be different (p < 0.05) from those seen at the outpatient clinic regarding: higher blood pressure; lower income; not belonging to the hospital community; greater alcohol intake; became aware of their hypertension because felt bad; measured blood pressure less often; did not take the medicine more often. In conclusion, unfavorable characteristics can contribute to hypertensive patients who do not follow antihypertension treatment adequately, leading to care in emergency units.

An economic evaluation of antihypertensive therapies based on clinical trials.

OBJECTIVE: Hypertension is a major issue in public health, and the financial costs associated with hypertension continue to increase. Cost-effectiveness studies focusing on antihypertensive drug combinations, however, have been scarce. The cost-effectiveness ratios of the traditional treatment (hydrochlorothiazide and atenolol) and the current treatment (losartan and amlodipine) were evaluated in patients with grade 1 or 2 hypertension (HT1-2). For patients with grade 3 hypertension (HT3), a third drug was added to the treatment combinations: enalapril was added to the traditional treatment, and hydrochlorothiazide was added to the current treatment. METHODS: Hypertension treatment costs were estimated on the basis of the purchase prices of the antihypertensive medications, and effectiveness was measured as the reduction in systolic blood pressure and diastolic blood pressure (in mm Hg) at the end of a 12-month study period. RESULTS: When the purchase price of the brand-name medication was used to calculate the cost, the traditional treatment presented a lower cost-effectiveness ratio [US$/mm Hg] than the current treatment in the HT1-2 group. In the HT3 group, however, there was no difference in cost-effectiveness ratio between the traditional treatment and the current treatment. The cost-effectiveness ratio differences between the treatment regimens maintained the same pattern when the purchase price of the lower-cost medication was used. CONCLUSIONS: We conclude that the traditional treatment is more cost-effective (US$/mm Hg) than the current treatment in the HT1-2 group. There was no difference in cost-effectiveness between the traditional treatment and the current treatment for the HT3 group.

Ambulatory Blood Pressure Monitoring: Five Decades of More Light and Less Shadows / Monitorização Ambulatorial da Pressão Arterial: Cinco Décadas de mais Luzes e Menos Sombras

Abstract Casual blood pressure measurements have been extensively questioned over the last five decades. A significant percentage of patients have different blood pressure readings when examined in the office or outside it. For this reason, a change in the paradigm of the best manner to assess blood pressure has been observed. The method that has been most widely used is the Ambulatory Blood Pressure Monitoring - ABPM. The method allows recording blood pressure measures in 24 hours and evaluating various parameters such as mean BP, pressure loads, areas under the curve, variations between daytime and nighttime, pulse pressure variability etc. Blood pressure measurements obtained by ABPM are better correlated, for example, with the risks of hypertension. The main indications for ABPM are: suspected white coat hypertension and masked hypertension, evaluation of the efficacy of the antihypertensive therapy in 24 hours, and evaluation of symptoms. There is increasing evidence that the use of ABPM has contributed to the assessment of blood pressure behaviors, establishment of diagnoses, prognosis and the efficacy of antihypertensive therapy. There is no doubt that the study of 24-hour blood pressure behavior and its variations by ABPM has brought more light and less darkness to the field, which justifies the title of this review.

Resumo Nas últimas cinco décadas muito têm sido questionadas as medidas casuais da pressão arterial (PA). Significativa porcentagem de pacientes apresenta PA muito diversa quando examinados na clínica ou fora dela. Por isso, é hoje observada uma mudança de paradigma com relação ao melhor modo de se avaliar a PA. O método que mais se consolidou é a Monitorização Ambulatorial da Pressão Arterial - MAPA. É possível obter-se o registro de medidas de PA durante 24 horas avaliando-se vários parâmetros como: médias de PA, cargas de pressão, áreas sob as curvas, variações entre vigília e sono, variabilidade de pressão de pulso etc. As medidas de PA obtidas pela MAPA são mais bem correlacionadas, por exemplo, com os riscos da hipertensão arterial. As principais indicações para a MAPA são: suspeita de hipertensão do avental branco e da hipertensão mascarada, avaliação da eficácia terapêutica nas 24 horas e avaliação de sintomas. Crescem as evidências de que o emprego da MAPA contribui para avaliar os comportamentos da PA, estabelecer diagnósticos, prognóstico e avaliar a eficácia terapêutica anti-hipertensiva. Sem dúvidas, o estudo do comportamento da PA e suas variações durante as 24 horas pela MAPA nos deixaram com menos sombras e mais luzes, e justifica o título desta revisão.

Doença renal crônica e fatores de risco para morte súbita cardíaca ­ denervação renal simpática: um sopro de esperança? / Chronic kidney disease and risk factors responsible for sudden cardiac death ­ renal sympathetic denervation: a whiff of hope?

Vários estudos têm demonstrado forte associação independente entre doença renal crônica e eventos cardiovasculares, incluindo morte, insuficiência cardíaca e infarto do miocárdio. Ensaios clínicos recentes estendem essa gama de eventos adversos cardiovasculares, incluindo também arritmias ventriculares e morte súbita cardíaca. Além disso, outros estudos sugerem remodelação estrutural do coração e alterações eletrofisiológicas nessa população. Esses processos podem explicar o aumento do risco de arritmia na doença renal crônica e ajudam a identificar os pacientes que possuem maior risco de morte súbita cardíaca. A hiperatividade simpática é bem conhecida por aumentar o risco cardiovascular em pacientes com doença renal crônica e é uma marca registrada do estado hipertensivo essencial, que ocorre precocemente no curso clínico da doença. Nessa afecção, a hiperatividade simpática parece ser expressa em sua fase clínica mais precoce, mostrando relação direta com a gravidade do estágio da insuficiência renal, sendo mais acentuada em sua fase terminal. A atividade nervosa simpática eferente e aferente na insuficiência renal é mediadora-chave para manutenção e progressão da doença. O objetivo desta revisão foi mostrar que o circuito fechado de realimentação do ciclo, em decorrência da hiperatividade adrenérgica, também agrava muitos dos fatores de risco responsáveis por causar morte súbita cardíaca, podendo ser um alvo potencial modificável pela denervação renal simpática percutânea. Pouco se sabe, ainda, sobre a viabilidade e a eficácia da denervação renal simpática percutânea na doença renal terminal

Several studies have shown a strong independent association between chronic kidney disease and cardiovascular events, including death, heart failure, and myocardial infarction. Recent clinical trials extend this array of adverse cardiovascular events, also including ventricular arrhythmias and sudden cardiac death. Furthermore, other studies suggest structural remodeling of the heart and electrophysiological alterations in this population. These processes may explain the increased risk of arrhythmia in kidney disease and help to identify patients who are at increased risk of sudden cardiac death. Sympathetic hyperactivity is well known to increase cardiovascular risk in chronic kidney disease patients and is typical of the essential hypertensive state that occurs early in the clinical course of the disease. In chronic kidney disease, sympathetic hyperactivity seems to be expressed at the earliest clinical stage of the disease, showing a direct relationship with the severity of renal failure, being more pronounced in the end stage of chronic kidney disease. Efferent and afferent sympathetic neural activity in kidney failure is a key mediator for the maintenance and progression of the disease. The aim of this review was to demonstrate that the feedback loop of this cycle, due to adrenergic hyperactivity, also aggravates many of the risk factors for sudden cardiac death and may be a potential target modifiable by percutaneous sympathetic renal denervation. Little is known whether it is feasible and effective in end-stage renal disease.