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This study supplies biological plausibility for observational studies on air pollution-related cardiovascular morbidity and mortality.

BackgroundBrazil is the world's largest producer of sugarcane. Harvest is predominantly manual, exposing workers to health risks: intense physical exertion, heat, pollutants from sugarcane burning.DesignPanel study to evaluate the effects of burnt sugarcane harvesting on blood markers and on cardiovascular system.MethodsTwenty-eight healthy male workers, living in the countryside of Brazil were submitted to blood markers, blood pressure, heart rate variability, cardiopulmonary exercise testing, sympathetic nerve activity evaluation and forearm blood flow measures (venous occlusion plethysmography) during burnt sugarcane harvesting and four months later while they performed other activities in sugar cane culture.ResultsMean participant age was 31±6.3 years, and had worked for 9.8±8.4 years on sugarcane work. Work during the harvest period was associated with higher serum levels of Creatine Kinase – 136.5 U/L (IQR: 108.5–216.0) vs. 104.5 U/L (IQR: 77.5–170.5), (p = 0.001); plasma Malondialdehyde–7.5±1.4 µM/dl vs. 6.9±1.0 µM/dl, (p = 0.058); Glutathione Peroxidase – 55.1±11.8 Ug/Hb vs. 39.5±9.5 Ug/Hb, (p<0.001); Glutathione Transferase– 3.4±1.3 Ug/Hb vs. 3.0±1.3 Ug/Hb, (p = 0.001); and 24-hour systolic blood pressure – 120.1±10.3 mmHg vs. 117.0±10.0 mmHg, (p = 0.034). In cardiopulmonary exercise testing, rest-to-peak diastolic blood pressure increased by 11.12 mmHg and 5.13 mmHg in the harvest and non-harvest period, respectively. A 10 miliseconds reduction in rMSSD and a 10 burst/min increase in sympathetic nerve activity were associated to 2.2 and 1.8 mmHg rises in systolic arterial pressure, respectively.ConclusionWork in burnt sugarcane harvesting was associated with changes in blood markers and higher blood pressure, which may be related to autonomic imbalance.

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AimsTo evaluate the feasibility, safety, and potential beneficial effects of left cardiac sympathetic denervation (LCSD) in systolic heart failure (HF) patients. Methods and resultsIn this prospective, randomized pilot study, inclusion criteria were New York Heart Association (NYHA) functional class II or III, left ventricular ejection fraction (LVEF) ≤40%, sinus rhythm, and resting heart rate .65 b.p.m., despite optimal medical therapy (MT). Fifteen patients were randomly assigned either to MT alone or MT plus LCSD. The primary endpoint was safety, measured by mortality in the first month of follow-up and morbidity according to prespecified criteria. Secondary endpoints were exercise capacity, quality of life, LVEF, muscle sympathetic nerve activity (MSNA), brain natriuretic peptide (BNP) levels and 24 h Holter mean heart rate before and after 6 months. We studied clinical effects in long-term follow-up. Ten patients underwent LCSD. There were no adverse events attributable to surgery. In the LCSD group, LVEF improved from 25 + 6.6 to 33 + 5.2 (P ¼ 0.03); 6 min walking distance improved from 167 + 35 to 198 + 47 m (P ¼ 0.02). Minnesota Living with Heart Failure Questionnaire (MLWHFQ) score physical dimension changed from 21 + 5 to 15 + 7 (P ¼ 0.06). The remaining analysed variables were unchanged. During 848 + 549 days of follow-up, in the MT group, three patients either died or underwent cardiac transplantation (CT), while in the LCSD group six were alive without CT. ConclusionsLCSD was feasible and seemed to be safe in systolic HF patients. Its beneficial effects warrant the development of a larger randomized trial.

The hypothesis of association between heart rate recovery and 24-hour heart rate variability in the first two minutes after exercise was not substantiated in this study. Heart rate recovery after exercise was associated with age and gender.

Heart rate variability (HRV) analysis is a useful method to assess abnormal functioning in the autonomic nervous system and to predict cardiac events in patients with heart failure (HF). HRV measurements with heart rate monitors have been validated with an electrocardiograph in healthy subjects but not in patients with HF. We explored the reproducibility of HRV in two consecutive six-minute walk tests (6MW), 60-minute apart, using a heart rate monitor (PolarS810i) and a portable electrocardiograph (called Holter) in 50 HF patients (mean age 59 years, NYHA II, left ventricular ejection fraction ~35%). The reproducibility for each device was analysed using a paired t-test or the Wilcoxon signed-rank test. Additionally, we assessed the agreement between the two devices based on the HRV indices at rest, during the 6MW and during recovery using concordance correlation coefficients (CCC), 95% confidence intervals and Bland-Altman plots. The test-retest for the HRV analyses was reproducible using Holter and PolarS810i at rest but not during recovery. In the second 6MW, patients showed significant increases in rMSSD and walking distance. The PolarS810i measurements had remarkably high concordance correlation [0.86

We investigated the relationship between blood pressure and the occurrence of complex ventricular arrhythmias (multiform, couplets, or runs) as assessed by 48-hour Holter monitoring in 74 stable long-term hemodialysis patients (44.5 +/- 12 years old; 54% men; 74% whites; dialysis duration, 51.3 +/- 36.1 months; systolic pressure, 146.6 +/- 19.3 mm Hg; diastolic pressure, 89.2 +/- 12.1 mm Hg; prevalence of arterial hypertension, 33.8%). Systolic and diastolic pressures represented the average of all predialysis determinations during the 3 months preceding the tests. Hemodialysis was performed midway through the Holter monitoring period. M-mode and bidimensional echocardiograms and myocardial perfusion tests were also obtained from all patients. Complex arrhythmias were observed in 37 individuals (50%). Univariate analysis showed that systolic pressure (P < .001), diastolic pressure (P < .05), age (P < .001), left ventricular posterior wall thickness (P < .01), left ventricular mass index (P < .05), and ischemic alterations on myocardial perfusion tests (P < .005) were significantly associated with complex arrhythmias. With the use of a multivariate model (stepwise logistic regression analysis) only systolic pressure (P < .01) and age (P < .05) were independently associated with complex arrhythmias. Sex; angina; dialysis duration; New York Heart Association functional class; use of digitalis; plasma levels of creatinine, sodium, potassium, calcium, and phosphate; hematocrit; left ventricular fractional shortening; left ventricular diastolic diameter; and ST segment deviation were not correlated with complex arrhythmias. The severity and frequency of complex arrhythmias were not influenced by hemodialysis. At follow-up (5 to 80 months) 5 patients had died of sudden death, 4 of whom were hypertensive and older than 45 years.(ABSTRACT TRUNCATED AT 250 WORDS)