Title : Association between physician-perceived functional class and functional capacity measured by exercise stress test in patients with heart failure and reduced ejection fraction
Abstract:
Introduction: The New York Heart Association (NYHA) functional classification is widely used in clinical practice, not only for the clinical and prognostic evaluation of Heart Failure (HF) pa ents but also for determining candidates for specific treatments. However, it is a subjective classification, in contrast to the exercise stress test, which is an accessible complementary examina on that allows for the objective assessment of functional capacity.
Aim: To evaluate the correlation and agreement between the NYHA functional classification as perceived by the physician and the exercise capacity assessed in the exercise test in patients with HFrEF and HFmrEF.
Methods: An observational, analytical and retrospective study was conducted in the Cardiology Department. It included 300 paients with HF and Left Ventricular Ejection Fraction (LVEF) < 50%, who underwent an exercise stress test between January 2018 and December 2022.
Results: Most patients were in NYHA functional class I (59.3%), with 36.7% in NYHA class II, and 4% in NYHA class III. The median LVEF was 39%, significantly lower in NYHA classes II and III (p < 0.001). The median of N-terminal pro B-type natriuretic peptide (NT-proBNP) was 780.50 pg/mL, with no significant differences among patients in NYHA classes I, II, or III (p = 0.192). The correlation between NYHA classes and functional capacity was 0.280 (p < 0.001), with an agreement of 0.150 (p = 0.000). The correlation between NYHA classes and heart rate recovery was 0.095 (p = 0.260).
Conclusions: A moderate correlation was found between the NYHA class perceived by the physician and the objectively measured functional capacity during the exercise stress test, despite a reduced agreement. On the other hand, the correlation between the NYHA class and heart rate recovery was considered insignificant.
