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 .
Combined cardiac resynchronization and implantable cardioversion defibrillation in advanced chronic heart failure: the MIRACLE ICD Trial.
CONTEXT Cardiac resynchronization therapy ( CRT ) through biventricular pacing is an effective treatment for heart failure ( HF ) with a wide QRS ; however , the outcomes of patients requiring CRT and implantable cardioverter defibrillator ( ICD ) therapy are unknown . OBJECTIVE To examine the efficacy and safety of combined CRT and ICD therapy in patients with New York Heart Association ( NYHA ) class III or IV congestive HF despite appropriate medical management . DESIGN , SETTING , AND PARTICIPANTS R and omized , double-blind , parallel-controlled trial conducted from October 1 , 1999 , to August 31 , 2001 , of 369 patients with left ventricular ejection fraction of 35 % or less , QRS duration of 130 ms , at high risk of life-threatening ventricular arrhythmias , and in NYHA class III ( n = 328 ) or IV ( n = 41 ) despite optimized medical treatment . INTERVENTIONS Of 369 r and omized patients who received devices with combined CRT and ICD capabilities , 182 were controls ( ICD activated , CRT off ) and 187 were in the CRT group ( ICD activated , CRT on ) . MAIN OUTCOME MEASURES The primary double-blind study end points were changes between baseline and 6 months in quality of life , functional class , and distance covered during a 6-minute walk . Additional outcome measures included changes in exercise capacity , plasma neurohormones , left ventricular function , and overall HF status . Survival , incidence of ventricular arrhythmias , and rates of hospitalization were also compared . RESULTS At 6 months , patients assigned to CRT had a greater improvement in median ( 95 % confidence interval ) quality of life score ( -17.5 [ -21 to -14 ] vs -11.0 [ -16 to -7 ] , P = .02 ) and functional class ( -1 [ -1 to -1 ] vs 0 [ -1 to 0 ] , P = .007 ) than controls but were no different in the change in distance walked in 6 minutes ( 55 m [ 44 - 79 ] vs 53 m [ 43 - 75 ] , P = .36 ) . Peak oxygen consumption increased by 1.1 mL/kg per minute ( 0.7 - 1.6 ) in the CRT group vs 0.1 mL/kg per minute ( -0.1 to 0.8 ) in controls ( P = .04 ) , although treadmill exercise duration increased by 56 seconds ( 30 - 79 ) in the CRT group and decreased by 11 seconds ( -55 to 12 ) in controls ( P<.001 ) . No significant differences were observed in changes in left ventricular size or function , overall HF status , survival , and rates of hospitalization . No proarrhythmia was observed and arrhythmia termination capabilities were not impaired . CONCLUSIONS Cardiac resynchronization improved quality of life , functional status , and exercise capacity in patients with moderate to severe HF , a wide QRS interval , and life-threatening arrhythmias . These improvements occurred in the context of underlying appropriate medical management without proarrhythmia or compromised ICD function
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 .