Stage C Heart Failure Corresponds to NYHA Class I-IV
Stage C heart failure encompasses patients with current or past symptoms of heart failure associated with underlying structural heart disease, and these patients can be in any NYHA functional class from I through IV. 1, 2
Understanding the Distinction Between Staging and Functional Classification
The ACC/AHA staging system and NYHA functional classification serve complementary but fundamentally different purposes:
Stage C is defined by symptom history, not current symptom severity—any patient who has ever experienced heart failure symptoms with structural heart disease is permanently classified as Stage C, regardless of whether treatment has rendered them currently asymptomatic 1, 2
NYHA class reflects current functional status and changes frequently in response to therapy or disease progression, while ACC/AHA stage progression is essentially unidirectional 1
The Full Spectrum of NYHA Classes Within Stage C
Stage C patients span the entire NYHA functional spectrum:
NYHA Class I (Stage C): Patients with prior heart failure symptoms who are now asymptomatic on treatment, with no limitation of physical activity 1
NYHA Class II (Stage C): Patients with slight limitation of physical activity; comfortable at rest but ordinary activity causes fatigue, palpitation, or dyspnea 1
NYHA Class III (Stage C): Patients with marked limitation of physical activity; comfortable at rest but less than ordinary activity causes symptoms 1
NYHA Class IV (Stage C): Patients unable to carry on any physical activity without discomfort, with symptoms present even at rest 1
Critical Clinical Implications
A Stage C patient in NYHA Class I still requires full guideline-directed medical therapy for heart failure with reduced ejection fraction (ACE inhibitors/ARBs, beta-blockers, mineralocorticoid receptor antagonists) because they have crossed the threshold into symptomatic disease, even if currently well-controlled 3
Stage C represents "the bulk of patients with heart failure" in clinical practice, distinguishing them from Stage B (structural disease but never symptomatic) and Stage D (refractory disease requiring advanced therapies) 1
The staging system was intentionally designed so patients cannot regress from Stage C back to Stage B, as having once developed the clinical syndrome of heart failure represents a permanent disease milestone 1