Understanding Heart Failure

By Rosalie McDonough, MD, MSc
Posted in Clinical Education

Heart failure is a heterogeneous syndrome that can be described along two complementary dimensions: disease stage and cardiac pump function. Staging reflects the progression of disease over time, from patients who are at risk but asymptomatic to those with advanced, treatment-refractory symptoms. In parallel, classification by left ventricular ejection fraction (LVEF) characterizes the underlying pattern of systolic function and helps guide diagnosis, prognosis, and therapy. Together, these frameworks provide a structured foundation for understanding where a patient is on the heart failure continuum and how best to approach management.

Illustration of heart failure using anatomical heart
Stages of heart failure
Stage Description
Stage A (At Risk) Risk factors present (hypertension, diabetes, obesity, CAD) without structural heart disease or symptoms
Stage B (Pre-HF) Structural heart disease or elevated biomarkers without current or prior symptoms
Stage C (Symptomatic HF) Structural heart disease with current or prior symptoms
Stage D (Advanced HF) Persistent symptoms interfering with daily life despite optimized therapy

Table 1. The American Heart Association and the American College of Cardiology have identified the four stages of heart failure described above1

Classification by left ventricular ejection fraction (LVEF)
Classification LVEF Description
HFrEF (reduced) ≤40% Reduced systolic function
HFmrEF (mildly reduced) 41–49% Mildly reduced systolic function
HFpEF (preserved) ≥50% Preserved systolic function with evidence of elevated filling pressures
HFimpEF (improved) Baseline ≤40%, now >40% Improved ejection fraction with prior systolic dysfunction

Table 2. Classification based on heart pump function, as defined be left ventricular ejection fraction (LVEF)1, 2

Prevalence and burden

Heart failure affects approximately 7.4 million US adults (3.0% prevalence) as of 2023. Globally, an estimated 55–64 million people live with heart failure, underscoring its public health impact.3,4  For individuals who survive to age 45, the lifetime risk of developing heart failure is 20–46%, depending on sex and race.3

Prevalence increases sharply with age, affecting fewer than 2% of adults under 60, but greater than 10% in those older than 75 years.5  By 2050, US prevalence is projected to nearly double to over 11 million, with healthcare costs exceeding $140 billion.4

Notably, approximately 50% of heart failure cases are heart failure with preserved ejection fraction (HFpEF), a proportion that continues to increase due to improved recognition, an aging population, and rising obesity prevalence.3

The problem of delayed or missed diagnosis

Heart failure is frequently diagnosed late, often only after symptoms have been present for months to years, and the patient presents with acute decompensation requiring hospitalization. Evidence from large observational studies highlights diagnostic delays and high rates of misdiagnosis (Table 3). 

Finding Source
79% of HF diagnoses were first recorded in hospital, not primary care UK linked data study (n=36,748)6
Median time from symptom presentation to diagnosis: 972 days (IQR 337–1468) UK primary care study7
Only 24% of symptomatic patients followed a guideline-aligned diagnostic pathway UK primary care study6
Misdiagnosis rates: 16–68.5% depending on setting Systematic review (n=223,859)8
COPD is the most common misdiagnosis: HF unrecognized in 20.5% of COPD patients Systematic review8

Table 3. Key findings from the literature

Why is heart failure missed?

Heart failure is commonly under-recognized in early stages due to a combination of patient, clinical, and system-level factors. Recent consensus statements and Delphi analyses highlight several recurring barriers to timely diagnosis9,10,11 :

Patient-level factors:

  • Limited awareness about HF symptoms
  • Under-reporting of symptoms (especially exertional dyspnea)
  • Symptom misattribution to aging, deconditioning, or other comorbidities
  • Younger age (<50), making providers less likely to consider HF

Clinical factors:

  • Non-specific symptoms (dyspnea, fatigue, edema) overlap with COPD, obesity, anemia, depression
  • Multimorbidity obscuring the diagnosis
  • Obesity can limit physical exam accuracy, imaging quality, and cause falsely low BNP levels12
  • Absence of classic congestion signs in chronic HF due to compensatory mechanisms13

System-level factors:

  • Limited access to natriuretic peptide testing and echocardiography in primary care
  • Variable HF knowledge among non-cardiology providers
  • Fragmented care between primary care and specialist services
Common presenting features of heart failure
Illustration showing symptoms of heart failure

Cardinal symptoms (present in ~80% at diagnosis)13,14

  • Dyspnea
  • Fatigue and reduced exercise tolerance
  • Ankle/peripheral edema
  • Weight gain from fluid retention

Subtle or atypical symptoms that may signal early or worsening HF13,15

  • Gastrointestinal symptoms, e.g., nausea, early satiety, abdominal bloating, right upper quadrant discomfort (intestinal/hepatic congestion)
  • Nocturnal cough
  • Wheeze misattributed to asthma/COPD ("cardiac asthma")

Physical examination findings13,16

  • Elevated jugular venous pressure (most sensitive sign)
  • S3 gallop
  • Displaced apical impulse
  • Positive abdominojugular reflux
  • Peripheral edema, ascites
Summary
  • Heart failure is common, underdiagnosed, and frequently identified late in its course.
  • The disease often progresses silently for years before clinical recognition.
  • Symptoms are non-specific and overlap with other chronic conditions.
  • Diagnostic delays reflect patient, clinical, and system-level factors.
  • Early stages of heart failure exist long before overt decompensation.
References

1. Universal Definition and Classification of Heart Failure: A Report of the Heart Failure Society of America, Heart Failure Association of the European Society of Cardiology, Japanese Heart Failure Society and Writing Committee of the Universal Definition of Heart Failure: Endorsed by the Canadian Heart Failure Society, Heart Failure Association of India, Cardiac Society of Australia and New Zealand, and Chinese Heart Failure Association. Bozkurt B, Coats AJS, Tsutsui H, et al. European Journal of Heart Failure. 2021;23(3):352-380. doi:10.1002/ejhf.2115.

2. 2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Heidenreich PA, Bozkurt B, Aguilar D, et al. Journal of the American College of Cardiology. 2022;79(17):e263-e421. doi:10.1016/j.jacc.2021.12.012.

3. Heart Failure With Preserved Ejection Fraction: A Review. Redfield MM, Borlaug BA. JAMA. 2023;329(10):827-838. doi:10.1001/jama.2023.2020.

4. Prioritising the Primary Prevention of Heart Failure. Khan SS, Berwanger O, Fiuzat M, et al. Lancet (London, England). 2025;406(10508):1138-1153. doi:10.1016/S0140-6736(25)01393-5.

5. Heart Failure. Metra M, Teerlink JR. Lancet (London, England). 2017;390(10106):1981-1995. doi:10.1016/S0140-6736(17)31071-1.

6. Routes to Diagnosis of Heart Failure: Observational Study Using Linked Data in England. Bottle A, Kim D, Aylin P, et al. Heart (British Cardiac Society). 2018;104(7):600-605. doi:10.1136/heartjnl-2017-312183.

7. Adherence to Guidelines in Management of Symptoms Suggestive of Heart Failure in Primary Care. Hayhoe B, Kim D, Aylin PP, et al. Heart (British Cardiac Society). 2019;105(9):678-685. doi:10.1136/heartjnl-2018-313971.

8. Misdiagnosis of Heart Failure: A Systematic Review of the Literature. Wong CW, Tafuro J, Azam Z, et al. Journal of Cardiac Failure. 2021;27(9):925-933. doi:10.1016/j.cardfail.2021.05.014.

9. Heart Failure Diagnosis in the General Community - Who, How and When? A Clinical Consensus Statement of the Heart Failure Association (HFA) of the European Society of Cardiology (ESC). Docherty KF, Lam CSP, Rakisheva A, et al. European Journal of Heart Failure. 2023;25(8):1185-1198. doi:10.1002/ejhf.2946.

10. Developing Core Indicators for Identifying People at Risk of Delayed Heart Failure Diagnosis. Barber K, Bernhardt L, McCann GP, et al. BMC Primary Care. 2025;26(1):316. doi:10.1186/s12875-025-03024-4.

11. Heart Failure With Preserved Ejection Fraction: Everything the Clinician Needs to Know. Campbell P, Rutten FH, Lee MM, Hawkins NM, Petrie MC. Lancet (London, England). 2024;403(10431):1083-1092. doi:10.1016/S0140-6736(23)02756-3.

12. Assessment of the Patient With Heart Failure Symptoms and Risk Factors: A Guide for the Non-Cardiologist. Arnold SV. Diabetes, Obesity & Metabolism. 2023;25 Suppl 3:15-25. doi:10.1111/dom.15166.

13. Heart Failure With Reduced Ejection Fraction: A Review. Murphy SP, Ibrahim NE, Januzzi JL. JAMA. 2020;324(5):488-504. doi:10.1001/jama.2020.10262.

14. Dilated Cardiomyopathy. Weintraub RG, Semsarian C, Macdonald P. Lancet (London, England). 2017;390(10092):400-414. doi:10.1016/S0140-6736(16)31713-5.

15. State of the Science: The Relevance of Symptoms in Cardiovascular Disease and Research: A Scientific Statement From the American Heart Association. Jurgens CY, Lee CS, Aycock DM, et al. Circulation. 2022;146(12):e173-e184. doi:10.1161/CIR.0000000000001089.

16. 2019 ACC Expert Consensus Decision Pathway on Risk Assessment, Management, and Clinical Trajectory of Patients Hospitalized With Heart Failure: A Report of the American College of Cardiology Solution Set Oversight Committee. Hollenberg SM, Warner Stevenson L, Ahmad T, et al. Journal of the American College of Cardiology. 2019;74(15):1966-2011. doi:10.1016/j.jacc.2019.08.001.

Medical advice disclaimer

DISCLAIMER: THE CONTENT SET FORTH HEREIN DOES NOT PROVIDE MEDICAL ADVICE NOR IS AN ATTEMPT TO PRACTICE MEDICINE

The information, including but not limited to, text, graphics, images, and other material contained on this website are for informational purposes only. No material on this website or document are intended to be a substitute for professional medical education, advice, diagnosis, or treatment

About the Author

Rosalie McDonough, MD, MSc
Rosalie McDonough, MD, MSc - Clinician Scientist

Rosalie McDonough, MD, MSc, is a clinician scientist with a diverse background in medical research and clinical practice. She earned her Master of Science degree from McGill University in Montreal, Canada, later completing her medical degree at the University Medical Center Hamburg-Eppendorf in Hamburg, Germany. Dr. McDonough’s career has spanned various fields within medicine, focusing on clinical research and health technology. Her interests have encompassed cardiopulmonary disease, lung cancer, molecular cardiology, occupational medicine, and acute ischemic stroke imaging. She is currently the Director of Medical Affairs at Eko Health.