***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 
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    Input: Although beta-adrenoreceptor antagonists appear to be beneficial in chronic heart failure there is little information on their effects on autonomic and baroreceptor function which may have important prognostic implication s. We sought to determine first whether beta-adrenoreceptor blockade will improve baroreceptor function and vagal tone in chronic heart failure , and second whether there were any differences between st and ard therapy with metoprolol and the second-generation vasodilating beta-blocker celiprolol . In this double-blind r and omized placebo-controlled study 50 patients with stable chronic heart failure received either celiprolol 200 mg daily , metoprolol 50 mg twice daily or placebo for 12 weeks after a 4-week dose titration period . Thirty-five healthy normal subjects were also studied .  Baroreceptor gain was assessed non-invasively by cross-spectral analysis of R-R and systolic blood pressure low- and high-frequency components ( the alpha angle ) during controlled respiration . High-frequency power was used as a measure of vagal modulation . Satisfactory recordings for analysis were obtained in 31 patients with heart failure . The results showed that at baseline baroreceptor gain ( alphaHF ) was significantly depressed in patients with heart failure compared with the normal control group ( 4.95+/-0 . 55 versus 11.73+/-1.32 ms/mmHg , P<0.0001 ) . After 12 weeks of treatment with metoprolol  baroreceptor gain improved significantly whether measured while supine ( P=0.03 ) or st and ing ( P=0.009 ) , and this was associated with a significant increase in R-R HF power ( P=0 . 008 ) . There were no significant changes after treatment with celiprolol or placebo . We conclude that metoprolol but not celiprolol therapy restores baroreceptor gain towards normal and increases vagal tone in chronic heart failure . The ancillary properties of celiprolol do not appear to provide any advantages over metoprolol for the restoration of autonomic and baroreceptor function in heart failure CONTEXT Observational studies have shown that psychosocial factors are associated with increased risk for cardiovascular morbidity and mortality , but the effects of behavioral interventions on psychosocial and medical end points remain uncertain . OBJECTIVE To determine the effect of 2 behavioral programs , aerobic exercise training and stress management training , with routine medical care on psychosocial functioning and markers of cardiovascular risk . DESIGN , SETTING , AND PATIENTS R and omized controlled trial of 134 patients ( 92 male and 42 female ; aged 40 - 84 years ) with stable ischemic heart disease ( IHD ) and exercise-induced myocardial ischemia . Conducted from January 1999 to February 2003 . INTERVENTIONS Routine medical care ( usual care ) ; usual care plus supervised aerobic exercise training for 35 minutes 3 times per week for 16 weeks ; usual care plus weekly 1.5-hour stress management training for 16 weeks . MAIN OUTCOME MEASURES Self-reported measures of general distress ( General Health Question naire [ GHQ ] ) and depression ( Beck Depression Inventory [ BDI ] ) ; left ventricular ejection fraction ( LVEF ) and wall motion abnormalities ( WMA ) ; flow-mediated dilation ; and cardiac autonomic control ( heart rate variability during deep breathing and baroreflex sensitivity ) . RESULTS Patients in the exercise and stress management groups had lower mean ( SE ) BDI scores ( exercise : 8.2 [ 0.6 ] ; stress management : 8.2 [ 0.6 ] ) vs usual care ( 10.1 [ 0.6 ] ; P = .02 ) ; reduced distress by GHQ scores ( exercise : 56.3 [ 0.9 ] ; stress management : 56.8 [ 0.9 ] ) vs usual care ( 53.6 [ 0.9 ] ; P = .02 ) ; and smaller reductions in LVEF during mental stress testing ( exercise : -0.54 % [ 0.44 % ] ; stress management : -0.34 % [ 0.45 % ] ) vs usual care ( -1.69 % [ 0.46 % ] ; P = .03 ) . Exercise and stress management were associated with lower mean ( SE ) WMA rating scores ( exercise : 0.20 [ 0.07 ] ; stress management : 0.10 [ 0.07 ] ) in a subset of patients with significant stress-induced WMA at baseline vs usual care ( 0.36 [ 0.07 ] ; P = .02 ) . Patients in the exercise and stress management groups had greater mean ( SE ) improvements in flow-mediated dilation ( exercise : mean [ SD ] , 5.6 % [ 0.45 % ] ; stress management : 5.2 % [ 0.47 % ] ) vs usual care patients ( 4.1 % [ 0.48 % ] ; P = .03 ) . In a subgroup , those receiving stress management showed improved mean ( SE ) baroreflex sensitivity ( 8.2 [ 0.8 ] ms/mm Hg ) vs usual care ( 5.1 [ 0.9 ] ms/mm Hg ; P = .02 ) and significant increases in heart rate variability ( 193.7 [ 19.6 ] ms ) vs usual care ( 132.1 [ 21.5 ] ms ; P = .04 ) . CONCLUSION For patients with stable IHD , exercise and stress management training reduced emotional distress and improved markers of cardiovascular risk more than usual medical care alone AIMS Reduced heart rate variability is associated with an unfavourable prognosis in patients with ischaemic heart disease . Whether physical training can modify this risk factor is not definitely proven . Our hypothesis was that training might increase both physical capacity and heart rate variability in elderly patients recovering from an acute coronary event , i.e. acute myocardial infa rct ion ( n=38 ) or an episode of unstable angina ( n=27 ) . METHODS AND RESULTS 24 h ambulatory ECG recordings were obtained from 65 patients r and omized to either a 3 months supervised outpatient group training programme 50 min  three times a week ( n=29 ) or to a control group ( n=36 ) . The two groups were well balanced as regards demographic data and pharmacological treatment at the time of r and omization . Body mass index and pharmacological therapy remained unchanged during the study . Heart rate variability was analysed in the time and frequency domains . At the 3 month follow-up , exercise tolerance had increased from 103 to 120 W in the training group ( P<0.001 ) , and from 102 to 106 W in the control group ( ns ) . The time-domain heart rate variability measures SDNN ( st and ard deviation of all filtered RR intervals over the analysed time period ) and SDANN ( st and ard deviation of the means of all filtered RR intervals for all 5 min epochs of the analysed time period ) increased significantly during the daytime in the training group ( P<0.01 and P<0.05 , respectively ) , but not in the control group . A significant improvement in night-time heart rate variability was observed among controls . There was a statistically significant correlation ( P<0.05 ) between changes in 24 h overall power ( frequency domain measure ) and changes in maximal exercise capacity in the training group . CONCLUSION A regular aerobic group training programme after an acute coronary event can significantly improve exercise capacity and modify heart rate variability in a prognostically favourable direction in elderly low-to-intermediate risk patients , recovering from an acute coronary event BACKGROUND AND PURPOSE Cardiac autonomic dysfunction is associated with risk of restenosis and cardiovascular mortality in patients after percutaneous transluminal coronary angioplasty ( PTCA ) . Analysis of heart rate variability ( HRV ) is an important , widely used method for assessing cardiac autonomic regulation . The purpose of this study was to investigate the effect of exercise training on HRV in subjects after PTCA . SUBJECTS AND METHODS A total of 84 subjects who had undergone PTCA were recruited for this study . The subjects ( age [mean+/-SD]=57.0+/-9.3 years ) were r and omly assigned to either an exercise group to undergo an 8-week outpatient exercise program or a control group to undergo usual care .  Heart rate variability was measured for 5 minutes in the supine resting position at baseline and at the end of 8 weeks . RESULTS The parasympathetically modulated HRV of the subjects in the exercise group increased significantly compared with the HRV of subjects in the control group . The effects of training on HRV were independent of angioplasty type ( balloon or stent ) and were unrelated to whether the subjects had received previous PTCA . DISCUSSION AND CONCLUSION Exercise training can increase parasympathetic modulation of cardiac function in people after they have undergone successful PTCA . Our results suggest that analysis of HRV can be extended to assess the effect of exercise training on cardiac autonomic dysfunction in people after coronary angioplasty To investigate the effects of carteolol , which is a nonselective beta-adrenergic agent with intrinsic sympathomimetic activity , on silent myocardial ischemia , exercise-induced myocardial ischemia , indexes of heart rate variability , and pain-modulating system , 20 patients ( mean 60 + /- 9 years ) with chronic stable angina underwent exercise treadmill testing and 24-hour ambulatory electrocardiographic monitoring during 2 weeks of carteolol administration ( 15 mg/day ) in a double-blind , placebo-controlled design . Plasma levels of beta-endorphin and bradykinin and electrical pain stimulation to the skin were measured at rest and peak exercise . Indexes of heart rate variability of both time-domain and frequency-domain analysis were derived from 24-hour ambulatory electrocardiographic monitoring . Carteolol decreased maximal heart rate responses to daily activities during ambulatory monitoring and significantly reduced the median frequency and duration of silent myocardial ischemic episodes ( from 1.0 to 0.0 events/24 hr and from 16 to 0 min/24 hr , respectively ) . Carteolol significantly decreased the rate-pressure product at rest and during exercise with improving maximal ST segment depression , suggesting amelioration of exercise-induced myocardial ischemia . Carteolol did not significantly affect plasma levels of beta-endorphin and bradykinin or pain threshold . It significantly decreased some indexes ( st and ard deviation of all normal sinus R-R intervals in the entire 24-hour recording and st and ard deviation of the mean of all 5-minute segments of normal R-R intervals of a 24-hour recording ) of heart rate variability . These results suggest that carteolol may reduce total myocardial ischemic burden by the reduction of cardiac oxygen dem and during daily activities and exercise stress , while not affecting plasma levels of beta-endorphin , bradykinin , and pain threshold . Because carteolol tended to decrease indexes of heart rate variability , significant caution might be necessary in prescribing the beta-blocking agents with intrinsic sympathomimetic activity like carteolol to patients with potential serious arrhythmia Background It is unclear how much of the reduction in cardiac mortality in coronary heart disease ( CHD ) patients with exercise training  is the result of direct effects on the heart and coronary vasculature , or to indirect effects , via primary risk factors . Objective The aim of this article was to quantify the cardiac mortality benefits of exercise-based rehabilitation attributable to risk factor reductions versus the direct effects on the heart and vasculature . Methods The IMPACT coronary heart disease model was used to examine the reduction in cardiac mortality attributable to changes in risk factors from a meta- analysis of cardiac rehabilitation r and omized , controlled trials . Patients were receiving rehabilitation following an acute myocardial infa rct ion , angina pectoris or revascularization . Outcomes considered were primary risk factors ( total cholesterol , systolic blood pressure and smoking behaviour ) and cardiac mortality . Results Nineteen exercise-only cardiac rehabilitation trials ( including 2984 patients ) were identified . Across these trials , exercise training reduced pooled cardiac mortality by 28 % ( relative risk , 0.72 , 95 % confidence interval 0.55–0.95 ) , with 30 fewer deaths than in the control group . Applying the CHD model , approximately 17 ( 58 % ) of these 30 fewer deaths were attributable to reductions in major cardiovascular risk factors : 7.1 deaths ( minimum estimate 6.2 , maximum estimate 9.5 ) attributable to an 18 % reduction in smoking prevalence ; 5.9 deaths ( minimum −0.6 , maximum 12.6 ) to a 0.11 mmol/l reduction in cholesterol , and 4.4 deaths ( −1.0 minimum , 6.7 maximum ) to a 2.0 mmHg reduction in systolic blood pressure . Conclusions Approximately half of the 28 % reduction in cardiac mortality achieved with exercise-based cardiac rehabilitation may be attributed to reductions in major risk factors , particularly smoking . Eur J Cardiovasc Prev Rehabil 13:369–374 © 2006 The European Society of To investigate the effects of physical training on neurovegetative profile of patients with previous anterior myocardial infa rct ion ( MI ) , we studied 38 patients out of the EAMI study at 4 to 6 weeks after anterior MI ( test 1 ) , who were then assigned r and omly to a  training group ( n = 22 ) or to a  control group ( n = 16 ) and studied again 6 months later ( test 2 ) . Neurovegetative function was assessed by analyzing the heart rate variability ( HRV ) of 24 h , from ambulatory ECG recording , both in time domain , as st and ard deviation 
    Output:
    
Conclusion Pharmacologic , biobehavioral and exercise strategies for secondary prevention of CAD significantly increase HRV .