title: The influence of muscle mass, strength, fatigability and blood flow on exercise capacity in cachectic and non-cachectic patients with chronic heart failure.
abstract: BACKGROUND
  The influence of age, skeletal muscle function and peripheral blood flow on exercise capacity in chronic heart failure patients is controversial, possibly due to variations in skeletal muscle atrophy.
  
  
  RESULTS
  To assess predictors of exercise capacity in patients with clinical cardiac cachexia, we studied 16 cachectic and 39 non-cachectic male chronic heart failure patients of similar age and ejection fraction. All cachectic patients were wasted (% ideal body weight: 81.2 +/- 1.9 vs 105.2 +/- 2.1, P < 0.0001, mean +/- SEM) and had documented weight loss (5-30 kg). Peak oxygen consumption (14.9 +/- 1.4 vs 16.3 +/- 0.6 ml.kg-1, min-1, resting and peak blood flow (plethysmography) and 20 min fatigability (% baseline strength) were all similar between the two groups. Quadriceps strength, muscle size (all P < 0.0001), strength per unit muscle (right: P < 0.05: left: P < 0.001) and 5 min fatigability (P < 0.05) were all lower in cachectic patients. In non-cachectic patients, age (R = 0.48) and quadriceps strength (R = 0.43, all P < 0.01) predicted peak oxygen consumption. Only in cachectic patients did peak blood flow predict peak oxygen consumption significantly (R = 0.72, P = 0.005), whereas age and strength did not. Similar findings were confirmed using other previously published definitions of cardiac cachexia.
  
  
  CONCLUSIONS
  The predictors of exercise capacity change with the development of cardiac cachexia from age and strength to peak blood flow. This shift may be caused by additional endocrine or catabolic, abnormalities active in end stage heart failure.
authors.affiliation: Department of Cardiac Medicine, Imperial College and Royal Brompton Hospital, London, U.K.
authors.forename: S D
authors.initials: SD
authors.lastname: Anker
authors.forename: J W
authors.initials: JW
authors.lastname: Swan
authors.forename: M
authors.initials: M
authors.lastname: Volterrani
authors.forename: T P
authors.initials: TP
authors.lastname: Chua
authors.forename: A L
authors.initials: AL
authors.lastname: Clark
authors.forename: P A
authors.initials: PA
authors.lastname: Poole-Wilson
authors.forename: A J
authors.initials: AJ
authors.lastname: Coats
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D015992:Body Mass Index; D002100:Cachexia / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D002395:Catecholamines / Q000097:blood; D002908:Chronic Disease; D017079:Exercise Tolerance / Q000502:physiology*; D006333:Heart Failure / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism / Q000503:physiopathology*; D010101:Oxygen Consumption; D010991:Plethysmography; D011237:Predictive Value of Tests; D013318:Stroke Volume
chemical_list: D002395:Catecholamines