Pharmacological trials including patients with more severe heart failure were more likely to show a significant improvement with therapy than trials of milder heart failure .
Using mean values in these trials , the age of patients appeared a more important determinant of 6MWT distance than New York Heart Association classification .
The 6MWT has not yet been proven to be a robust test for the identification of effective pharmacological interventions although it appears useful for the assessment of cardiac resynchronization therapy .
The results of the 6MWT were concordant with changes in symptoms , suggesting that it may be used as supportive evidence for symptom benefit .
AIMS The 6 min walk test ( 6MWT ) is commonly used in clinical trials to assess treatments for heart failure , but its ability to distinguish between effective and ineffective treatments is question able .
The aim of this study is to investigate , using a systematic literature review , the utility of the 6MWT as a measure of the effectiveness of treatment in r and omized controlled trials of heart failure .
Beneficial effects of metoprolol on myocardial sympathetic function: Evidence from a randomized, placebo-controlled study in patients with congestive heart failure.
BACKGROUND We sought to investigate whether beta-blockers exert a presynaptic effect in the myocardium as measured by 123I-metaiodobenzylguanidine . METHODS The study comprised 59 patients with congestive heart failure , New York Heart Association class II or III , and left ventricular ejection fraction < 35 % . After an open label titration phase , patients were r and omized to their maximal tolerable dose of metoprolol or placebo .  Myocardial MIBG uptake was measured before the titration phase and after 6 months of treatment . Other parameters were maximal oxygen consumption , 6-minute walking test , plasma neurohormones , and echocardiographic parameters . RESULTS We found a 21.9 % increase in mean myocardial MIBG uptake after 6 months of treatment with metoprolol . In contrast , MIBG uptake decreased by 7.8 % in the placebo group ( P = 0.03 compared with metoprolol ) . Left ventricular end-diastolic diameter decreased from 74 + /- 11 mm to 67 + /- 10 mm ( P < .05 , within-group comparison ) and LVEF increased from 25.3 % + /- 7.4 % to 32.6 % + /- 9.6 % ( P < .05 , within-group comparison ) in the metoprolol group . Placebo-treated patients showed no significant changes . Comparison of changes in left ventricular end-diastolic diameter and LVEF between metoprolol and placebo did not reach statistical significance ( P = 0.2 ) . CONCLUSIONS This r and omized , placebo-controlled study demonstrates that metoprolol has a presynaptic effect as measured by myocardial MIBG scintigraphy in both ischemic and nonischemic cardiomyopathy
Pharmacological trials including patients with more severe heart failure were more likely to show a significant improvement with therapy than trials of milder heart failure .
Using mean values in these trials , the age of patients appeared a more important determinant of 6MWT distance than New York Heart Association classification .
The 6MWT has not yet been proven to be a robust test for the identification of effective pharmacological interventions although it appears useful for the assessment of cardiac resynchronization therapy .
The results of the 6MWT were concordant with changes in symptoms , suggesting that it may be used as supportive evidence for symptom benefit .
AIMS The 6 min walk test ( 6MWT ) is commonly used in clinical trials to assess treatments for heart failure , but its ability to distinguish between effective and ineffective treatments is question able .
The aim of this study is to investigate , using a systematic literature review , the utility of the 6MWT as a measure of the effectiveness of treatment in r and omized controlled trials of heart failure .