Limitations of the New York Heart Association functional classification system and self-reported walking distances in chronic heart failure
- Claire Raphael1,
- Cathy Briscoe2,
- Justin Davies2,
- Zachary Ian Whinnett3,
- Charlotte Manisty3,
- Richard Sutton4,
- Jamil Mayet2,
- Darrel P Francis2
- 1Imperial College of Science Technology and Medicine, London, UK
- 2International Centre for Circulatory Health, St Mary’s Hospital, London, UK
- 3National Heart and Lung Institute, London, UK
- 4Department of Cardiology, Royal Brompton Hospital, London, UK
- Correspondence to:
Dr C Raphael
International Centre for Circulatory Health, St Mary’s Hospital and Imperial College, 59 North Wharf Road, London W2 1LA, UK;
- Accepted 15 August 2006
- Published Online First 27 September 2006
Background: Two ways to evaluate the symptoms of heart failure are the New York Heart Association (NYHA) classification and asking patients how far they can walk (walk distance). The NYHA system is commonly used, although it is not clear how individual clinicians apply it.
Aim: To investigate how useful these measures are to assess heart failure and whether other questions might be more helpful.
Methods: 30 cardiologists were asked what questions they used when assessing patients with heart failure. To assess interoperator variability, two cardiologists assessed a series of 50 patients in classes II and III using the NYHA classification. 45 patients who had undergone cardiopulmonary testing were interviewed using a specially formulated questionnaire. They were also asked how far they could walk before being stopped by symptoms, and then tested on their ability to estimate distance.
Results: The survey of cardiologists showed no consistent method for assessing NYHA class and a literature survey showed that 99% of research papers do not reference or describe their methods for assigning NYHA classes. The interoperator variability study showed only 54% concordance between the two cardiologists. 70% of cardiologists asked patients for their walk distance; however, this walk distance correlated poorly with actual exercise capacity measured by cardiopulmonary testing (ρ = 0.04, p = 0.82).
Conclusion: No consistent method of assessing NYHA class is in use and the interoperator study on class II and class III patients gave a result little better than chance. Some potential questions are offered for use in assessment. Walking distance, although frequently asked, does not correlate with formally measured exercise capacity, even after correction for patient perception of distance, and has never been found to have prognostic relevance. Its value is therefore doubtful.
Published Online First 27 September 2006
Competing interests: None.
Ethical approval: Ethical approval was granted for this study.
Contribution: All authors contributed to the planning and analysis of the study, and interpretation of the results, as well as to the writing of the paper. CR, CB and CM designed and implemented the questionnaire, performed the walk study and the analysis of past studies using NYHA. ZIW and JD designed and implemented the exercise testing and interpretation of the physiological data. RS, JM and DPF designed and managed the overall study and planned the analysis methods. All authors have approved the final manuscript.