Six-minute walk test and cardiopulmonary exercise testing in patients with chronic heart failure: a comparative analysis on clinical and prognostic insights

Circ Heart Fail. 2009 Nov;2(6):549-55. doi: 10.1161/CIRCHEARTFAILURE.109.881326. Epub 2009 Sep 28.


Background: The six-minute walk test (6MWT) and cardiopulmonary exercise testing (CPET) are the 2 testing modalities most broadly used for assessing functional limitation in patients with heart failure (HF). A comprehensive comparison on clinical and prognostic validity of the 2 techniques has not been performed and is the aim of the present investigation.

Methods and results: Two hundred fifty-three patients diagnosed with systolic (n=211) or diastolic (n=42) HF (age: 61.9+/-10.1 years; New York Heart Association Class: 2.2+/-0.78) underwent a 6MWT and a symptom-limited CPET evaluation and were prospectively followed up. During the 4-year tracking period, there were 43 cardiac-related deaths with an annual cardiac mortality rate of 8.7%. The 6MWT distance correlated with CPET-derived variables (ie, peak Vo(2), Vo(2) at anaerobic threshold, and Ve/Vco(2) slope) and was significantly reduced in proportion with lower peak Vo(2) and higher Ve/Vco(2) slope classes and presence of an exercise oscillatory breathing (EOB) pattern (P<0.01). However, no significant differences were observed in distance covered between survivors and nonsurvivors (353.2+/-95.8 m versus 338.5+/-76.4 m; P=NS). At univariate and multivariate Cox proportional analyses, the association of the 6MWT distance with survival was not significant either as a continuous or dicotomized variable (< or =300 m). Conversely, CPET-derived variables emerged as prognostic with the strongest association found for EOB (systolic HF) and Ve/Vco(2) slope (entire population with HF and patients with a 6MWT< or =300 m).

Conclusions: The 6MWT is confirmed to be a simple and reliable first-line test for quantification of exercise intolerance in patients with HF. However, there is no supportive evidence for its use as a prognostic marker in alternative to or in conjunction with CPET-derived variables.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Cardiovascular System / physiopathology*
  • Chronic Disease
  • Electrocardiography
  • Exercise Test*
  • Exercise Tolerance*
  • Female
  • Follow-Up Studies
  • Heart Failure, Diastolic / diagnosis*
  • Heart Failure, Diastolic / mortality
  • Heart Failure, Diastolic / physiopathology
  • Heart Failure, Diastolic / therapy
  • Heart Failure, Systolic / diagnosis*
  • Heart Failure, Systolic / mortality
  • Heart Failure, Systolic / physiopathology
  • Heart Failure, Systolic / therapy
  • Humans
  • Male
  • Middle Aged
  • Oxygen Consumption
  • Predictive Value of Tests
  • Proportional Hazards Models
  • Prospective Studies
  • Reproducibility of Results
  • Respiratory Function Tests
  • Respiratory Mechanics
  • Respiratory System / physiopathology*
  • Risk Assessment
  • Severity of Illness Index
  • Time Factors
  • Treatment Outcome
  • Ventricular Function, Left
  • Walking*