Background: Stratification of the severity of heart failure has major prognostic and therapeutic implications.
Aims: To prospectively compare different methods of assessment of functional capacity in patients with chronic heart failure (CHF).
Methods and results: We studied 143 patients (78 male and 65 female) with CHF aged less than 70 years (mean 57.3 years). Functional assessment was made clinically according to NYHA classification and according to the Goldman Activity Scale Classification (GASC). Cardiovascular performance was measured by peak O(2) consumption (pVO(2)) and anaerobic threshold (AT) at cardiopulmonary exercise test and by the distance walked during a 6-min walk test (6-MWT). Clinical scales resulted significantly related. Peak VO(2) and AT showed a mild relation with distance covered at 6-MWT (r=0.56 and r=0.46, respectively). Concordance between NYHA classification and levels of performance at cardiopulmonary exercise test or at 6-MWT was less than 50%.
Conclusion: Our results suggest that none of the usually employed methods give a definitive assessment of functional capacity of cardiovascular system and a high degree of discordance exists among the results of different tests in the same patient. Although NYHA classification maintains its value in clinical evaluation of patients with CHF, the 6-min walk test is recommended in patients with mild-to-moderate CHF (II-III NYHA classes) as a simple and useful screening test to select patients for further diagnostic evaluation.