Saturated Fat Intake Is Related to Heart Rate Variability in Women with Polycystic Ovary Syndrome.

BACKGROUND/AIMS: There is a heightened risk for cardiovascular diseases in women with polycystic ovary syndrome (PCOS). Alterations in heart rate variability (HRV) may reflect subclinical cardiovascular disease, with a putative association between HRV and dietary fat. This study evaluated HRV in PCOS and control women based on the dietary intake of saturated fatty acid (SFA). METHODS: Biochemical/hormonal profile, resting metabolic rate, physical activity, HRV in response to the Stroop test, and dietary intake were assessed in 84 PCOS and 54 control women stratified by median SFA intake in the PCOS group (8.5% of daily energy intake). RESULTS: Body mass index (p = 0.041), blood pressure (p < 0.01), and HOMA-IR (p = 0.003) were higher in PCOS vs. CONTROLS: PCOS women had higher testosterone (p = 0.001), dehydroepiandrosterone sulfate (p = 0.012), and free androgen index (p = 0.001), and lower sex hormone-binding globulin levels than controls (p = 0.001). In both groups, the clinical profile and calorie intake were similar between SFA categories. In PCOS, testosterone was lower when SFA intake <8.5%. PCOS women with SFA <8.5% consumed more beans, fruits, and vegetables and had better frequency and time domain HRV indices. No differences in HRV were detected between SFA categories in controls. In PCOS, age and SFA intake were independent predictors of HRV. CONCLUSIONS: Lower SFA intake is related to improved cardiovascular autonomic function in PCOS.

Effect of transcutaneous electrical nerve stimulation on muscle metaboreflex in healthy young and older subjects.

Transcutaneous electrical nerve stimulation (TENS) increases local blood flow. It is not known whether increase in blood flow may be caused by inhibition of sympathetic activity, mediated by muscle metaboreflex activity. The purpose of this study was to evaluate the effect of TENS on metaboreflex activation and heart rate variability (HRV) in young and older individuals. Eleven healthy young (age 25 ± 1.3 years) and 11 healthy older (age 63 ± 4.2 years) were randomized to TENS (30 min, 80 Hz, 150 µs) or placebo (same protocol without electrical output) applied on the ganglion region. Frequency domain indices of HRV and hemodynamic variables were evaluated during the pressor response to static handgrip exercise at 30% of maximal voluntary contraction, followed by recovery with (PECO+) or without (PECO-) circulatory occlusion, in a randomized order. At the peak exercise, the increase in mean blood pressure was attenuated by TENS (P < 0.05), which was sustained during PECO+ and PECO-. TENS promoted a higher calf blood flow and lower calf vascular resistance during exercise and recovery. Likewise, TENS induced a reduction in the estimated muscle metaboreflex control both in young (placebo: 28 ± 4 units vs. TENS: 6 ± 3, P < 0.01) and in older individuals (placebo: 13 ± 3 units vs. TENS: 5 ± 3, P < 0.01). HRV analysis showed similar improvement in sympatho-vagal balance with TENS in young and older individuals. We conclude that application of TENS attenuates blood pressure and vasoconstrictor responses during exercise and metaboreflex activation, associated with improved sympatho-vagal balance in healthy young and older individuals.

Autonomic modulation in patients with congenital generalized lipodystrophy (Berardinelli-Seip syndrome).

AIMS: This study was designed to assess cardiac autonomic regulation in congenital generalized lipodystrophy (CGL) patients using 24 h heart rate variability (HRV). METHODS AND RESULTS: A cross-sectional study was carried out to evaluate 18 patients with CGL and 19 healthy controls matched by sex and age. We measured blood pressure, plasma concentrations of glucose, triglycerides, cholesterol, high-density lipoprotein-cholesterol, insulin resistance by the homeostatic model assessment (HOMA-R), left ventricular mass (LVM) (by two-dimensional echocardiography), and 24 h HRV (by the time domain indices MeanRR, SDNN, and rMSSD). Compared with controls, CGL patients had higher blood pressure (systolic, 131.1 vs. 106.3 mmHg, P < 0.05; diastolic, 85.0 vs. 68.2 mmHg, P < 0.05) and 10 patients met criteria for arterial hypertension and concentric left ventricular hypertrophy (LVM index > or =115 g/m(2)and relative left ventricular wall thickness > or =0.42). Patients with CGL had higher levels of glucose, triglycerides, cholesterol, and HOMA-R and 12 met criteria for type 2 diabetes mellitus. Compared with controls, CGL patients had lower MeanRR (639.8 vs. 780.5 ms, P < 0.001), SDNN (79.2 vs. 168.5 ms, P < 0.001), and rMSSD (15.8 vs. 59.6 ms, P < 0.001). In CGL patients, the reduction in HRV was independent of the metabolic and haemodynamic disturbances. CONCLUSION: Congenital generalized lipodystrophy patients have abnormal autonomic modulation, reflected by increased heart rate and pronounced reduction in HRV, independent of the metabolic and haemodynamic disturbances observed in this disorder.

Detection of arteriolar narrowing in fundoscopic examination: evidence of a low performance of direct ophthalmoscopy in comparison with a microdensitometric method.

BACKGROUND: Retinal abnormalities, particularly arteriolar narrowing, are powerful predictors of cardiovascular events. The precision of internists and ophthalmologists in the assessment of retinal vessels widths has been disputed but not evaluated against a technology of edge detection. METHODS: Fifty-two patients with hypertension had optic fundi examination done by an internist and an ophthalmologist, and had retinographies taken and digitized to determine vessel diameters by a new technology of edge detection (microdensitometric method). Physicians asserted the presence of arteriolar narrowing (

Cholinesterase inhibition reduces arrhythmias in asymptomatic Chagas disease.

INTRODUCTION: Parasympathetic dysfunction may play a role in the genesis of arrhythmias in Chagas disease. AIM: This study evaluates the acute effects of pyridostigmine (PYR), a reversible cholinesterase inhibitor, on the occurrence of arrhythmias in patients with Chagas cardiac disease. METHOD: Following a double-blind, randomized, placebo-controlled, cross-over protocol, 17 patients (age 50±2 years) with Chagas cardiac disease type B underwent 24-hour Holter recordings after oral administration of either pyridostigmine bromide (45 mg, 3 times/day) or placebo (PLA). RESULTS: Pyridostigmine reduced the 24-hours incidence (median [25%-75%]) of premature ventricular beats-PLA: 2998 (1920-4870), PYR: 2359 (940-3253), P=.044; ventricular couplets-PLA: 84 (15-159), PYR: 33 (6-94), P=.046. Although the total number of nonsustained ventricular tachycardia in the entire group was not different (P=.19) between PLA (1 [0-8]) and PYR (0 [0-4]), there were fewer episodes under PYR in 72% of the patients presenting this type of arrhythmia (P=.033). CONCLUSION: Acute administration of pyridostigmine reduced the incidence of nonsustained ventricular arrhythmias in patients with Chagas cardiac disease. Further studies that address the use of pyridostigmine by patients with Chagas cardiac disease under a more prolonged follow-up are warranted.

Spontaneous breathing trial in T-tube negatively impact on autonomic modulation of heart rate compared with pressure support in critically ill patients.

INTRODUCTION: Spontaneous breathing with a conventional T-piece (TT) connected to the tracheal tube orotraqueal has been frequently used in clinical setting to weaning of mechanical ventilation (MV), when compared with pressure support ventilation (PSV). However, the acute effects of spontaneous breathing with TT versus PSV on autonomic function assessed through heart rate variability (HRV) have not been fully elucidated. OBJECTIVE: The purpose of this study was to examine the acute effects of spontaneous breathing in TT vs PSV in critically ill patients. METHOD: Twenty-one patients who had received MV for ≥ 48 h and who met the study inclusion criteria for weaning were assessed. Eligible patients were randomized to TT and PSV. Cardiorespiratory responses (respiratory rate -ƒ, tidal volume-VT , mean blood pressure (MBP) and diastolic blood pressure (DBP), end tidal dioxide carbone (PET CO2 ), peripheral oxygen saturation (SpO2 ) and HRV indices in frequency domain (low-LF, high frequency (HF) and LF/HF ratio were evaluated. RESULTS: TT increased ƒ (20 ± 5 vs 25 ± 4 breaths/min, P<0.05), MBP (90 ± 14 vs 94 ± 18 mmHg, P<0.05), HR (90 ± 17 vs 96 ± 12 beats/min, P<0.05), PET CO2 (33 ± 8 vs 48 ± 10 mmHg, P<0.05) and reduced SpO2 (98 ± 1.6 vs 96 ± 1.6%, P<0.05). In addition, LF increased (47 ± 18 vs 38 ± 12 nu, P<0.05) and HF reduced (29 ± 13 vs 32 ± 16 nu, P<0.05), resulting in higher LF/HF ratio (1.62 ± 2 vs 1.18 ± 1, P<0.05) during TT. Conversely, VT increased with PSV (0.58 ± 0.16 vs 0.50 ± 0.15 L, P<0.05) compared with TT. CONCLUSION: Acute effects of TT mode may be closely linked to cardiorespiratory mismatches and cardiac autonomic imbalance in critically ill patients.

Effects of aerobic exercise intensity on ambulatory blood pressure and vascular responses in resistant hypertension: a crossover trial.

BACKGROUND: Resistant hypertension often exposes patients to poor blood pressure (BP) control, resulting in clinical vulnerability, possible need for device-based procedures (denervation) and increased therapy costs. Regular exercise markedly benefits patients with hypertension, including resistant patients. However, little is known about short-term exercise effects in resistant hypertension. OBJECTIVE: To evaluate acute hemodynamic effects of exercise in resistant hypertension. METHOD: After maximal exercise testing, 20 patients (54.0 ±â€Š5.7 years, 30.2 ±â€Š4.9 kg/m) with resistant hypertension participated in three crossover interventions, in random order, and on separate days: control (45' of rest), and light intensity and moderate intensity (45' of aerobic exercise at 50 and 75% of maximum heart rate, respectively). Ambulatory BP, forearm blood flow (with subsequent calculation of vascular resistance), and reactive hyperemia were measured before and after interventions trough venous occlusion plethysmography. RESULTS: Compared with control, both exercise intensities reduced ambulatory systolic pressure over 5 h (light: -7.7 ±â€Š2.4 mmHg and moderate: -9.4 ±â€Š2.8 mmHg, P < 0.01), whereas only light intensity reduced diastolic pressure (-5.7 ±â€Š2.2 mmHg, P < 0.01). Light intensity also lowered systolic and diastolic pressures over 10-h daytime (-3.8 ±â€Š1.3 and -4.0 ±â€Š1.3 mmHg, respectively, P < 0.02), night-time (-6.0 ±â€Š2.4 and -6.1 ±â€Š1.6 mmHg, respectively, P < 0.05), and diastolic pressure over 19 h (-4.8 ±â€Š1.2 mmHg, P < 0.01). Forearm blood flow changed (decreased) compared with baseline only at 50 min after light intensity (P < 0.05). After the control and light intensity sessions, vascular resistance increased at the end of 1 h, and after moderate intensity, it decreased only at the moment (∼2 min) immediately after intervention (P < 0.05). CONCLUSION: A single session of light or moderate aerobic exercise acutely reduces ambulatory BP in resistant hypertension, although benefits persist longer following light intensity.

Measuring arteriolar-to-venous ratio in retinal photography of patients with hypertension: development and application of a new semi-automated method.

BACKGROUND: The extent of arteriolar narrowing has been recognized as a major sign of end-organ damage in patients with hypertension, but most methods used for its evaluation are highly dependent on the observer. We describe a new semi-automated method to measuring arteriolar-to-venous (A/V) ratio in retinal photography and present its application in the evaluation of patients with hypertension. METHODS: In a cross-sectional study, 58 patients with hypertension had retinographies taken and digitized to determine the vessel diameter by direct measurement (micrometric method) or by the new microdensitometric method. Sub-pixel resolution was obtained via cubic spline fitting of the edge of vessel walls. For each pair of adjacent pixels, 10 intermediate points were generated in the perpendicular direction of the wall. Vessel widths were automatically extracted from this synthetic curve, with cut-points defined where the exterior wall position equals the double of mean noise along the slice. RESULTS: The intra- and interobserver kappa statistics for the diagnosis of abnormal A/V ratio by the microdensitometric measurements were 0.93 (P < .0001) and 0.85 (P = .0005), respectively. Systolic blood pressure was inversely and significantly associated with the A/V ratio measured by the microdensitometric method. CONCLUSIONS: The microdensitometric method is reliable, is easy to operate, and captures the expected association between blood pressure and retinal vessels narrowing. Its performance in clinical practice and in the prediction of cardiovascular events should be confirmed in larger databases with retinographies.

Cholinergic stimulation with pyridostigmine reduces ventricular arrhythmia and enhances heart rate variability in heart failure.

BACKGROUND: Increased ventricular arrhythmia density and reduced heart rate variability are associated with risk of death in patients with heart failure. Cholinesterase inhibition with pyridostigmine bromide increases heart rate variability in normal subjects, but its effect on patients with heart failure is unknown. In this study, we tested the hypothesis that short-term administration of pyridostigmine bromide, a cholinesterase inhibitor, reduces ventricular arrhythmia density and increases heart rate variability in patients with congestive heart failure. METHODS: Patients with heart failure and in sinus rhythm participated in a double-blind, cross-over protocol, randomized for placebo and pyridostigmine (30 mg orally 3 times daily for 2 days). Twenty-four hour electrocardiographic recordings were performed for arrhythmia analysis and for the measurement of time domain indices of heart rate variability. Patients were separated into 2 groups, according to their ventricular arrhythmia density. The arrhythmia group (n = 11) included patients with >10 ventricular premature beats (VPBs) per hour (VPBs/h), and the heart rate variability group (n = 12) included patients with a number of VPBs in 24 hours not exceeding 1% of the total number of R-R intervals. RESULTS: For the arrhythmia group, pyridostigmine resulted in a 65% reduction of ventricular ectopic activity (placebo 266 +/- 56 VPBs/h vs pyridostigmine 173 +/- 49 VPBs/h, P =.03). For the heart rate variability group, pyridostigmine administration increased mean R-R interval (placebo 733 +/- 22 ms vs pyridostigmine 790 +/- 33 ms, P =.01), and in the time domain indices of heart rate variability root-mean-square of successive differences (placebo 21 +/- 2 ms vs pyridostigmine 27 +/- 3 ms, P =.01) and percentage of pairs of adjacent R-R intervals differing by >50 ms (placebo 3% +/- 1% vs pyridostigmine 6% +/- 2%, P =.03). CONCLUSION: In patients with heart failure, pyridostigmine reduced ventricular arrhythmia density and increased heart rate variability, most likely due to its cholinomimetic effect. Long-term trials with pyridostigmine in heart failure should be conducted.

Short-term folinic acid supplementation improves vascular reactivity in HIV-infected individuals: a randomized trial.

OBJECTIVE: HIV-infected individuals present a cluster of conditions that activate or injure the vascular endothelium. The administration of folates may exert beneficial effects on endothelial function in different populations at risk for cardiovascular disease. The aim of this study was to determine the effects of 4 wk of folinic acid supplementation on forearm vascular responses during reactive hyperemia in HIV-infected patients under highly active antiretroviral therapy. METHODS: This was a prospective, randomized, double-blind, placebo-controlled trial to compare the effects of 4 wk of daily ingestion of 5 mg of folinic acid (n = 15) or placebo (n = 15). Participants had to have been on antiretroviral therapy (ART) for at least 6 mo before enrollment, with undetectable viral load, and CD4 cell count >200 cells/mm(3). Vascular function was evaluated with venous occlusion plethysmography at baseline and after 4 wk, for the determination of brachial artery reactive hyperemia, and after isosorbide dinitrate administration. RESULTS: The groups were comparable. The mean age of patients was 45 y; there were eight women in each group. There was no difference regarding ART regimen. The supplementation of folinic acid produced a significant improvement in reactive hyperemia (from 14.9 to 21.2 mL•min•100 mL). The same was not observed in placebo group (from 15.3 to 14.6 mL•min•100 mL; group P, 0.017; time P < 0.001; interaction P < 0.001). Endothelium-independent responses remained unchanged. CONCLUSIONS: Short-term folinic acid supplementation improved vascular reactivity in HIV-infected individuals enrolled in the studied. As folate supplementation is safe and relatively inexpensive, long-term clinical trials should be conducted.

Acute ingestion of alcohol and cardiac autonomic modulation in healthy volunteers.

Arrhythmogenic effects of alcohol may be intermediated by its effects over heart rate variability (HRV). Most studies about the effects of alcohol over HRV were observational and did not explore the temporal influence of alcohol ingestion over autonomic modulation. The aim of this study was to verify if an acute ingestion of alcohol has a time-dependent influence over time-domain indices of HRV. The effect of the ingestion of 60 g of ethanol or placebo over autonomic modulation was compared in healthy men (35 per group), with 18-25 years of age, before and during 17 h after ingestion. Alcohol promoted a fall in the standard deviation of all normal R-R intervals, root mean square of successive differences, and percentage of pairs of adjacent R-R intervals differing by more than 50 ms and in two indices of the three-dimensional return map, by a period up to 10 h after the ingestion of alcohol, accompanied by an increase in heart rate. The indices returned to values similar of the control group 10 h after ingestion. The effects over HRV indices were attenuated by adjustment for heart rate. The ingestion of alcohol induces a broad cardiovascular adaptation secondary to vagal withdrawal and sympathetic activation that may be responsible for arrhythmogenic effects of alcohol ingestion.

Hormone replacement therapy does not affect the 24-hour heart rate variability in postmenopausal women: results of a randomized, placebo-controlled trial with two regimens.

Postmenopausal women are at greater risk of coronary heart disease. The results of previous studies of the effects of hormone replacement therapy (HRT) on cardiac autonomic modulation in postmenopausal women have been contradictory. This study examined whether continuous treatment for 3 months with estradiol alone (ERT) or with estradiol plus norethisterone (HRT), increases 24-hour heart rate variability (HRV) in postmenopausal women. In this double-blind, placebo-controlled trial, 40 healthy postmenopausal women, 46-63 years of age, were randomly assigned to (1) continuous 2 mg of estradiol plus 1 mg of norethisterone acetate daily (HRT, n = 13), or (2) 2 mg of estradiol daily (ERT, n = 14), or (3) placebo (n = 13). Before and after 3 months of therapy, blood estradiol concentrations were measured and 24-hour electrocardiograms recorded for evaluation of 24-hour time-domain indices of HRV, and indices derived from the three-dimensional return map. Both hormone replacement regimens significantly increased blood estradiol concentrations, while no change occurred in the placebo group. In the three treatment groups, multiple 24-hour time-domain indices of HRV and indices derived from the three-dimensional return map remained unchanged. In healthy postmenopausal women, HRT with estradiol or estradiol and norethisterone for 3 months did not modify cardiac autonomic activity evaluated by 24-hour indices of HRV. These findings are consistent with a lack of protective cardiovascular effect of HRT described in recent large randomized trials.