***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: ABSTRACT Objective To analyze respiratory mechanics and hemodynamic alterations in an experimental model of chronic heart failure ( CHF ) following myocardial infa rct ion . Method Twenty-seven male adult Wistar rats were r and omized to CHF group ( n=12 ) or Sham group ( n=15 ) . Ten weeks after coronary ligation or sham surgery , the animals were anesthetized and su bmi tted to respiratory mechanics and hemodynamic measurements . Pulmonary edema as well as cardiac remodeling were measured . Results The CHF rats showed pulmonary edema 26 % higher than the Sham group . The respiratory system compliance ( Crs ) and the total lung capacity ( TLC ) were lower ( 40 % and 27 % , respectively ) in the CHF rats when compared to the Sham group ( P<0.01 ) . There was also an increase in tissue resistance ( Gti ) and elastance ( Hti ) ( 28 % and 45 % , respectively ) in the CHF group . Moreover , left ventricular end-diastolic pressure was higher ( 32 mmHg vs 4 mmHg , P<0.01 ) , while the left ventricular systolic pressure was lower ( 118 mmHg vs 130 mmHg , P=0.02 ) in the CHF group when compared to the control . Pearson ’s correlation coefficient showed a negative association between pulmonary edema and Crs ( r=–0.70 , P=0.0001 ) and between pulmonary edema and TLC ( r=–0.67 , P=0.0034 ) . Pulmonary edema correlated positively with Gti ( r=0.68 , P=0.001 ) and Hti ( r=0.68 , P=0.001 ) . Finally , there was a strong positive relationship between pulmonary edema and heart weight ( r=0.80 , P=0.001 ) . Conclusion Rats with CHF present important changes in hemodynamic and respiratory mechanics , which may be associated with alterations in cardiopulmonary interactions Background —Although heart failure is common among women with coronary disease , the risk factors for developing heart failure have not been well studied . We determined the risk factors for developing heart failure among postmenopausal women with established coronary disease . Methods and Results —This is a prospect i ve cohort study using data from the Heart and Estrogen/progestin Replacement Study ( HERS ) , a r and omized , blinded , placebo-controlled trial of 4.1 years ’ duration , and subsequent open-label observational follow-up for 2.7 years ( HERS II ) , performed at 20 US clinical centers between 1993 and 2000 . Of the 2763 postmenopausal women with established coronary disease in the HERS trial , we studied the 2391 women with no heart failure at baseline by self-report and physical examination .  The primary outcome of this analysis was incident heart failure defined by hospital admission or death from heart failure . During the 6.3±1.4-year follow-up , 237 women ( 10 % ) developed heart failure . Nine predictors were identified : diabetes ( defined as a self-reported history of diabetes on treatment ) , atrial fibrillation , myocardial infa rct ion , creatinine clearance < 40 mL/min , systolic blood pressure > 120 mm Hg , current smoking , body mass index > 35 kg/m2 , left bundle-branch block , and left ventricular hypertrophy . R and omization to estrogen/progestin was not associated with heart failure ( hazard ratio=1.0 ; 95 % CI , 0.7 to 1.3 ) . Diabetes was the strongest risk factor ( adjusted hazard ratio=3.1 ; 95 % CI , 2.3 to 4.2 ) . Diabetic women with elevated body mass index or depressed creatinine clearance were at highest risk , with annual incidence rates of 7 % and 13 % , respectively . Among diabetic women , hyperglycemia was associated with heart failure risk ( adjusted hazard ratio=3.0 ; 95 % CI , 1.2 to 7.5 for fasting glucose > 300 mg/dL compared with fasting glucose 80 to 150 mg/dL ) . Conclusions —We identified 9 predictors of heart failure in postmenopausal women with coronary disease . Diabetes was the strongest risk factor , particularly when poorly controlled or with concomitant renal insufficiency or obesity BACKGROUND The effect of home-based exercise training on neurovascular control in heart failure patients is unknown . AIMS To test the hypothesis that home-based training would maintain the reduction in muscle sympathetic nerve activity ( MSNA ) and forearm vascular resistance ( FVR ) acquired after supervised training . METHODS AND RESULTS Twenty-nine patients ( 54+/-1.9 years , EF<40 % ) were r and omised into two groups : untrained control ( n=12 ) and exercise trained  ( n=17 ) . Both groups underwent assessment of Quality of Life ( QoL ) , MSNA , and forearm blood flow . The exercise group underwent a 4-month supervised training program followed by 4 months of home-based training . After the initial 4 months of training , patients in the exercise group showed a significant increase in peak VO(2 ) and reduction in MSNA , compared to the untrained group , but this was not maintained during 4 months of home-based training . In contrast , the decrease in FVR ( 56+/-3 vs. 46+/-4 vs. 40+/-2 U , p=0.008 ) and the improvement in QOL that were achieved during supervised training were maintained during home-based training . CONCLUSIONS Home-based training following supervised training is a safe strategy to maintain improvements in QoL and reduction in FVR in chronic heart failure patients , but is an inadequate strategy to maintain fitness as estimated by peak VO(2 ) or reduction in neurohumoral activation This article introduces the approach of GRADE to rating  quality of evidence .  GRADE specifies four categories-high , moderate , low , and very low-that are applied to a body of evidence , not to individual studies . In the context of a systematic review , quality reflects our confidence that the estimates of the effect are correct . In the context of recommendations , quality reflects our confidence that the effect estimates are adequate to support a particular recommendation . R and omized trials begin as high- quality evidence , observational studies as low quality . " Quality " as used in GRADE means more than risk of bias and so may also be compromised by imprecision , inconsistency , indirectness of study results , and publication bias . In addition , several factors can increase our confidence in an estimate of effect . GRADE provides a systematic approach for considering and reporting each of these factors . GRADE separates the process of assessing quality of evidence from the process of making recommendations . Judgments about the strength of a recommendation depend on more than just the quality of evidence Stratification of the severity of heart failure has major prognostic and therapeutic implication s. OBJECTIVES The goal of this study was to test the hypothesis that exercise training reduces resting sympathetic neural activation in patients with chronic advanced heart failure . BACKGROUND Exercise training in heart failure has been shown to be beneficial , but its mechanisms of benefit remain unknown . METHODS Sixteen New York Heart Association class II to III heart failure patients , age 35 to 60 years , ejection fraction < or = 40 % were divided into two groups : 1 ) exercise-trained ( n = 7 ) , and 2 ) sedentary control ( n = 9 ) . A normal control exercise-trained group was also studied ( n = 8) . The four-month supervised exercise training program consisted of three 60 min exercise sessions per week , at heart rate levels that corresponded up to 10 % below the respiratory compensation point . Muscle sympathetic nerve activity ( MSNA ) was recorded directly from peroneal nerve using the technique of microneurography . Forearm blood flow was measured by venous plethysmography . RESULTS Baseline MSNA was greater in heart failure patients compared with normal controls ; MSNA was uniformly decreased after exercise training in heart failure patients ( 60 + /- 3 vs. 38 + /- 3 bursts/100 heart beats ) , and the mean difference in the change was significantly ( p < 0.05 ) greater than the mean difference in the change in sedentary heart failure or trained normal controls . In fact , resting MSNA in trained heart failure patients was no longer significantly greater than in trained normal controls . In heart failure patients , peak VO(2 ) and forearm blood flow , but not left ventricular ejection fraction , increased after training . CONCLUSIONS These findings demonstrate that exercise training in heart failure patients results in dramatic reductions in directly recorded resting sympathetic nerve activity . In fact , MSNA was no longer greater than in trained , healthy controls 
    Output:
    
CONCLUSION Exercise training could be effective in reducing sympathetic nerve activity in patients with heart failure .