Why can a patient with a history of atrial fibrillation (AF), symptoms of palpitations, productive cough, lethargy, and reduced effort tolerance be considered to have heart failure with reduced ejection fraction (HFrEF) even in the absence of fluid overload symptoms, and what is the staging name for this condition?

Heart Failure Without Fluid Overload: Understanding the Diagnosis and Staging

A patient can have heart failure with reduced ejection fraction (HFrEF) without fluid overload symptoms because heart failure is fundamentally a clinical syndrome of structural or functional cardiac impairment, not simply a state of congestion—the patient described has Stage C, NYHA Class I-II heart failure. 1

Why Heart Failure Exists Without Fluid Overload

Core Definition of Heart Failure

• Heart failure is defined as a complex clinical syndrome resulting from structural or functional impairment of ventricular filling or ejection, with cardinal manifestations including dyspnea, fatigue (which may limit exercise tolerance), and fluid retention. 1

• Critically, some patients present with exercise intolerance but little evidence of fluid retention, while others complain primarily of edema—this is why the term "heart failure" is preferred over "congestive heart failure." 1

• The diagnosis is largely clinical, based on careful history and physical examination, and there is no single diagnostic test for heart failure. 1

Symptoms Beyond Congestion

Your patient's presentation fits the non-congestive phenotype:

• Palpitations from atrial fibrillation indicate the arrhythmic burden that commonly precipitates or accompanies HFrEF. 2, 3

• Productive cough can result from pulmonary congestion that is not yet manifesting as overt peripheral edema or rales—early pulmonary vascular changes occur before classic "wet" signs. 4

• Lethargy and reduced effort tolerance directly reflect the reduced cardiac output state of HFrEF, independent of volume status. 1

• The poor correlation between ejection fraction and symptoms is well-established: patients with very low EF may be asymptomatic, while those with preserved LVEF may have severe disability. 1

Pathophysiologic Mechanisms

• Non-cardiac factors contribute substantially to exercise intolerance in ambulatory patients, including peripheral vascular dysfunction, skeletal muscle physiology alterations, pulmonary dynamics, neurohormonal activation, and reflex autonomic activity. 1

• These mechanisms explain why hemodynamic improvement from therapeutic interventions does not always correlate with symptomatic improvement. 1

• Atrial fibrillation itself can precipitate heart failure and is both a consequence and contributor to HFrEF progression, creating a bidirectional relationship that worsens outcomes. 2, 3

Staging Classification for This Patient

ACC/AHA Stage C Heart Failure

This patient has Stage C heart failure, defined as current or prior symptoms of heart failure associated with underlying structural heart disease (reduced ejection fraction). 1, 5

Key staging principles:

• 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 treatment response. 5

• The staging system is intentionally unidirectional: patients cannot regress from Stage C back to Stage B, as having once developed the clinical syndrome represents a permanent disease milestone. 5

• Stage C encompasses all NYHA functional classes (I-IV), meaning even asymptomatic patients on treatment who previously had symptoms remain Stage C. 1, 5

NYHA Functional Classification

Within Stage C, the functional status is determined by current symptoms:

• NYHA Class I (Stage C): Prior heart failure symptoms but now asymptomatic on treatment, with no limitation of physical activity. 5

• NYHA Class II (Stage C): Slight limitation of physical activity, comfortable at rest but experiencing fatigue, palpitation, or dyspnea with ordinary activity. 5

• Your patient with lethargy, reduced effort tolerance, and palpitations likely fits NYHA Class II, as symptoms occur with activity but not at rest. 1, 5

HFrEF Classification

• Heart failure with reduced ejection fraction (HFrEF) is defined as LVEF ≤40%. 1, 6

• The diagnosis requires not just reduced LVEF but clinical features of heart failure, ideally with biomarker evidence such as elevated natriuretic peptides (BNP >35 pg/mL or NT-proBNP >125 pg/mL). 1

Clinical Implications and Management Context

Prognostic Significance

• Atrial fibrillation and HFrEF together are associated with worse outcomes than either condition alone, including increased mortality, stroke risk, and heart failure hospitalizations. 2, 3, 7

• All-cause mortality is significantly higher in AF-HFrEF patients, with absolute death rates of 24% compared to 18% in AF-HFpEF over 2 years. 7

Treatment Priorities

• Stage C HFrEF requires guideline-directed medical therapy regardless of current symptom burden, as the structural abnormality represents "a point of no return unless progression is slowed or stopped by treatment." 5

• For AF in HFrEF, catheter ablation has shown superiority over medical therapy alone in reducing heart failure hospitalization (RR 0.57), cardiovascular mortality (RR 0.46), and all-cause mortality (RR 0.53), while improving LVEF and quality of life. 8

Common Pitfalls to Avoid

• Do not dismiss heart failure diagnosis based solely on absence of peripheral edema or pulmonary rales—these signs may be absent in early stages or well-treated patients. 1

• Do not confuse NYHA functional class with ACC/AHA stage—functional class changes with treatment, but stage progression is essentially unidirectional. 5

• Do not overlook the diagnostic value of elevated natriuretic peptides, which have high negative predictive value (0.94-0.98) for ruling out heart failure, though lower positive predictive value. 1