***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: To examine the effects of beta-adrenergic blockade on neurohormonal activation in patients with congestive heart failure , 15 men had assessment s of hemodynamics and supine peripheral renin and norepinephrine levels before and after 3 months of oral therapy with bucindolol  , a nonselective beta antagonist . At baseline , plasma renin activity did not correlate with any hemodynamic parameter . However , norepinephrine levels had a weak correlation with left ventricular end-diastolic pressure ( r = 0.74 , p less than 0.01 ) , stroke volume index ( r = 0.61 , p less than 0.02 ) and pulmonary vascular resistance ( r = 0.54 , p less than 0.05 ) . Plasma renin decreased with bucindolol therapy , from 11.6 + /- 13.4 to 4.3 + /- 4.1 ng/ml/hour ( mean + /- st and ard deviation ; p less than 0.05 ) , whereas plasma norepinephrine was unchanged , from 403 + /- 231 to 408 + /- 217 pg/ml . A wide diversity of the norepinephrine response to bucindolol was observed with reduction of levels in some patients and elevation in others . Although plasma norepinephrine did not decrease , heart rate tended to decrease ( from 82 + /- 20 vs 73 + /- 11 min-1 , p = 0.059 ) with beta-adrenergic blockade , suggesting neurohormonal antagonism at the receptor level . No changes in I-123 metaiodobenzylguanidine uptake occurred after bucindolol therapy , suggesting unchanged adrenergic uptake of norepinephrine with beta-blocker therapy . Despite reductions in plasma renin activity and the presence of beta blockade , the response of renin or norepinephrine levels to long-term bucindolol therapy did not predict which patients had improved in hemodynamic status ( chi-square = 0.37 for renin , 0.82 for norepinephrine ) . ( ABSTRACT TRUNCATED AT 250 WORDS UNLABELLED Plasma brain natriuretic peptide ( BNP ) level and cardiac autonomic function are closely related to prognosis in patients with heart failure . However , their correlation and incremental prognostic values in human heart failure are unclear . We sought to evaluate the correlation between BNP level and cardiac sympathetic innervation assessed by (123)I-metaiodobenzylguanidine ( (123)I-MIBG ) and the prognostic value of combined assessment of risk factors for mortality in patients with heart failure . METHODS After conventional examinations and measurements of plasma BNP level and heart-to-mediastinum ratio ( HMR ) of cardiac (123)I-MIBG activity , 158 patients with heart failure were prospect ively followed with an endpoint of cardiac death for 16 mo . RESULTS Fifteen deaths due to pump failure and 2 sudden cardiac deaths were documented . Plasma BNP level correlated with HMR significantly but not so tightly ( r = 0.330 , P < 0.0001 ) . Univariate analysis identified plasma BNP level , HMR , chronic renal dysfunction , diabetes mellitus , age , and use of nitrates as significant predictors of fatal pump failure , and multivariate Cox analysis showed that plasma BNP level was the most powerful predictor of cardiac death .  Patients with both plasma BNP level of > or = 172 pg/mL and late HMR of < or = 1.74 had a greater annual rate of fatal pump failure than did those without ( 17.5%/y vs. 0%-3.9%/y , respectively ) . The hazard ratio of plasma BNP level ( 7.2 ) or cardiac (123)I-MIBG activity ( 10.1 ) increased to 34.4 when both variables were used , and prevalence of fatal pump failure significantly increased from 22 % to 62.5 % when diabetes mellitus and chronic renal dysfunction were present with a higher plasma BNP level and low cardiac (123)I-MIBG activity . CONCLUSION Plasma BNP level is a stronger predictor than other risk factors for mortality in heart failure patients and is statistically significantly , but roughly , related to cardiac sympathetic nerve innervation . Impaired cardiac sympathetic nerve innervation and the presence of diabetes mellitus and chronic renal dysfunction , however , improve risk stratification of patients with heart failure and increased plasma BNP concentration UNLABELLED We evaluated whether spironolactone would improve cardiac sympathetic nerve activity and symptoms in patients with congestive heart failure ( CHF ) . METHODS Thirty patients with CHF ( left ventricular ejection fraction [ LVEF ] < 40 % ; mean , 30 % + /- 9 % ) were treated with an angiotensin-converting enzyme inhibitor , a loop diuretic , and , in most cases , digoxin . Fifteen patients ( group A ) were assigned to additionally receive spironolactone ( 12.5 - 50 mg/day ) , and the remaining 15 patients ( group B ) continued their current regimen . Patients were studied before and 6 mo after treatment . The delayed heart-to-mediastinum count ratio ( H/M ratio ) , delayed total defect score ( TDS ) , and washout rate ( WR ) were determined from (123)I-meta-iodobenzylguanidine ( MIBG ) images . LVEF was determined by echocardiography , and New York Heart Association ( NYHA ) functional class was estimated . RESULTS Before treatment , LVEF , TDS , H/M ratio , WR , and NYHA functional class were similar in both groups . With treatment , LVEF did not significantly improve in either group . However , after treatment in group A , TDS decreased from 37 + /- 9 to 25 + /- 13 ( P = 0.0001 ) , H/M ratio increased from 1.62 + /- 0.20 to 1.83 + /- 0.27 ( P < 0.0001 ) , and WR decreased from 51 + /- 9 to 40 + /- 15 ( P < 0.001 ) . In group B , these parameters did not significantly change . NYHA functional class improved in both groups ( in group A , from 3.3 + /- 0.5 to 1.7 + /- 0.5 [ P < 0.0001 ] ; in group B , from 3.3 + /- 0.5 to 2.4 + /- 0.6 [ P = 0.01 ] ) ; this was a significantly greater improvement in group A than in group B ( P < 0.01 ) . CONCLUSION Spironolactone improves cardiac sympathetic nerve activity and symptoms in patients with CHF 123I-metaiodobenzylguanidine ( 123I-MIBG ) is useful for assessment of the severity and prognosis of patients with chronic heart failure ( CHF ) . To examine 123I-MIBG kinetics in the early phase soon after tracer injection , we performed dynamic single photon emission computed tomography ( SPECT ) in 76 patients with CHF and 17 control subjects . The consecutive 15 images of 2 min-dynamic SPECT were acquired for 30 min after injection . From 0 to 4 min , a significant amount of radioactivity existed in the blood pool , thus we calculated washout rate of 123I-MIBG from 4 to 30 min ( % WR-E ) . Patients were followed up with an end-point of cardiac death or re-hospitalization for 16 months ( 6 - 30 months ) . As the NYHA functional class advanced , % WR-E increased ( control , NYHA class I , II , and III : 9 + /- 4 % , 10 + /- 5 % , 12 + /- 5 % , and 17 + /- 5 % * , respectively , * p < 0.01 vs. all other groups ) . Significant correlation was found between % WR-E and conventional WR from 30 min to 240 min ( r = 0.606 , p < 0.0001 ) . % WR-E was positively correlated with left ventricular end-diastolic dimension ( r = 0.372 , p < 0.01 ) and was inversely correlated with left ventricular fractional shortening ( r = -0.316 , p < 0.02 ) . The normal upper limit of % WR-E was defined as mean + 2SD value of 17 control subjects ( 17.1 % ) . Patients with abnormally rapid % WR-E levels had a higher cardiac event rate than those with normal % WR-E levels ( 57 % vs. 12 % , p < 0.0001 ) . These data suggest that washout rate of 123I-MIBG in the early phase from 4 min to 30 min ( % WR-E ) reflects cardiac sympathetic nervous integrity and is useful to evaluate the severity and prognosis of patients with CHF . The present results indicate a potential role of dynamic SPECT in shortening the 123I-MIBG imaging protocol OBJECTIVES We sought to evaluate the effects of spironolactone on cardiac sympathetic nerve activity and left ventricular ( LV ) remodeling in patients with dilated cardiomyopathy ( DCM ) . BACKGROUND Aldosterone prevents the uptake of norepinephrine and promotes structural remodeling of the heart . Spironolactone , an aldosterone receptor blocker , improves LV remodeling in patients with DCM , but its influence on cardiac sympathetic nerve activity has not been determined . METHODS We selected 30 patients with DCM who were treated with an angiotensin-converting enzyme inhibitor and a loop diuretic . Fifteen patients were assigned to receive spironolactone additionally , whereas the remaining 15 patients continued their current regimen . The delayed heart/mediastinum ( H/M ) count ratio , delayed total defect score ( TDS ) , and washout rate ( WR ) were determined from iodine-123 ( (123)I)-meta-iodobenzylguanidine ( MIBG ) images before and six months after treatment . The left ventricular end-diastolic volume ( LVEDV ) and left ventricular ejection fraction ( LVEF ) were determined by echocardiography , and New York Heart Association ( NYHA ) functional class was estimated . RESULTS In the spironolactone group , the TDS decreased from 36 + /- 9 to 24 + /- 13 ( p < 0.0001 ) , the H/M ratio increased from 1.64 + /- 0.20 to 1.86 + /- 0.27 ( p < 0.0001 ) , and WR decreased from 55 + /- 12 % to 41 + /- 15 % ( p < 0.0005 ) . In addition , the LVEDV decreased from 187 + /- 26 to 154 + /- 41 ml ( p < 0.005 ) , and LVEF increased from 33 + /- 6 % to 39 + /- 6 % ( p < 0.005 ) . However , there were no significant changes in these parameters in the control group . There was a significant correlation between changes in the (123)I-MIBG findings and changes in LVEDV with spironolactone treatment ( TDS : r = 0.684 , p = 0.0038 ; H/M ratio : r = -0.878 , p < 0.0001 ; and WR : r = 0.737 , p = 0.0011 ) . The NYHA functional class improved in both groups but showed a greater improvement in the spironolactone group than in the control group ( p < 0.01 ) . CONCLUSIONS Spironolactone improves cardiac sympathetic nerve activity and LV remodeling in patients with DCM Both myocardial m-[123I]iodobenzylguanidine ( 123I-MIBG ) uptake and plasma norepinephrine are markers of sympathetic activation in heart failure and have been shown to portend a poorer prognosis . However , these observations were noted before treatment with beta blockers became part of st and ard clinical practice . Fifty-eight patients with chronic heart failure ( New York Heart Association functional class II and III , ejection fraction < 35 % ; 53 % ischaemic cardiomyopathy ) were prospect ively studied with a mean follow-up of 36 months . During the observational period , 17 patients ( 29.3 % ) had a predefined event ( death and heart transplantation ) . All prognostic parameters were obtained before beta blocker therapy was initiated . In both uni- and multivariate analysis , the heart-mediastinum ratio of 123I-MIBG uptake did not correlate with cardiovascular mortality . In the multivariate Cox regression analysis , plasma norepinephrine , peak oxygen consumption , end-diastolic volume as measured by echocardiography and exercise performance during bicycling and walking had prognostic significance in patients with heart failure treated with beta blockers in addition to angiotensin-converting enzyme inhibitors UNLABELLED Cardiac (123)I-labeled metaiodobenzylguanidine ( MIBG ) activity has significant incremental prognostic value , but the difference between the long-term prognostic value of MIBG imaging for ischemic card 
    Output:
    
Our results indicate that patients with HF and decreased late H/M or increased myocardial MIBG washout have a worse prognosis compared with those with normal semi-quantitative myocardial MIBG parameters