Heart failure

Last updated: December 7, 2023

Summarytoggle arrow icon

Heart failure (HF) is a complex clinical syndrome caused by structural or functional impairment of ventricular filling and/or ejection of blood. The three main underlying causes of HF are coronary artery disease, diabetes mellitus, and hypertension; incidence increases with age. Typical clinical features include dyspnea and peripheral edema. The initial diagnostic workup includes measurement of natriuretic peptide levels, echocardiography, chest x-ray, and an ECG. Classification of patients based on left ventricular ejection fraction (LVEF), symptoms and functional capacity (NYHA class), and ACC/AHA stage helps guide management. Guideline-directed medical therapy for HF includes lifestyle modifications and treatment of associated conditions (e.g., hypertension) and comorbidities (e.g., anemia), along with a combination of pharmacological agents that reduce cardiac workload (e.g., SGLT2is, ARNIs, beta blockers, mineralocorticoid receptor antagonists). Treatment options for patients with advanced HF, a highly morbid condition, include device therapy for HF, mechanical circulatory support, and/or heart transplant. Acute heart failure (AHF) may occur as an exacerbation of HF (i.e., acute decompensated HF) or be caused by an acute cardiac condition such as myocardial infarction.

Definitiontoggle arrow icon

Preferred terminology [1][2][3]

The term “heart failure” is preferred over “congestive heart failure” because not all patients present with symptoms of fluid overload. [8]

Historical terminology [1][2]

Epidemiologytoggle arrow icon

  • Approx. 1.9% of the US population (6.2 million individuals) has HF. [9]
  • Incidence is higher among African American and Hispanic individuals. [10]
  • Incidence increases with age: Approx. 20% of individuals aged > 75 years are affected. [11]
  • An increasing proportion of patients with HF have HFpEF (≥ 50%). [1]

Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon

The three major causes of HF are CAD, hypertension, and diabetes mellitus. Patients typically have multiple risk factors that contribute to the development of HF.

Classificationtoggle arrow icon

Classification of HF by LVEF [1]

American College of Cardiology/American Heart Association (ACC/AHA) stages [1]

The ACC/AHA classification system categorizes patients based on an objective assessment of clinical features and diagnostic findings.

ACC/AHA stages of heart failure [1]
Stage Definition and criteria

Stage A: at risk for HF

  • Asymptomatic
Stage B: pre-HF
Stage C: symptomatic HF
Stage D: advanced HF
  • Symptoms of HF that disrupt daily life, with frequent hospitalizations despite GDMT optimization

Patients with stage C HF will always remain categorized as such, even if they become asymptomatic (i.e., NYHA class I) with treatment. [1]

New York Heart Association NYHA functional classification [1]

The NYHA classification system is used to assess limitations in physical activity and symptoms of patients with symptomatic HF (i.e., ACC/AHA stages C and D); it helps determine treatment eligibility and prognosis.

NYHA functional classification [1][2]
NYHA class Characteristics
Class I
  • No limitations in physical activity
  • No symptoms of HF
Class II
  • Mild symptoms and slight limitations during ordinary physical activity
  • No symptoms at rest
Class III
  • Marked limitations in physical activity
  • Less-than-ordinary activity causes symptoms.
  • Comfortable only at rest
Class IV
  • Severe limitations
  • Symptoms during any form of physical activity
  • Symptoms at rest

Pathophysiologytoggle arrow icon

Cardiac output, which is stroke volume times heart rate, is determined by three factors: preload, afterload, and ventricular contractility.

Underlying mechanism of reduced cardiac output

Consequences of decompensated heart failure

HF is characterized by reduced cardiac output that results in venous congestion and poor systemic perfusion.

Compensation mechanisms

The compensation mechanisms are meant to maintain the cardiac output when stroke volume is reduced.

Clinical featurestoggle arrow icon

General features of heart failure

Clinical features of left-sided heart failure

Clinical features of right-sided heart failure

Subtypes and variantstoggle arrow icon

High-output heart failure

Diagnosticstoggle arrow icon

See “Diagnosis of AHF” for the evaluation of acute decompensated HF.

General principles

Multiple conditions can mimic HF and/or impact therapeutic decisions, e.g., anemia or kidney or liver failure. No single laboratory finding, imaging study, or clinical feature either excludes or is diagnostic for HF. [1][2]

Clinical evaluation

Laboratory studies [1][20]

BNP or NT-proBNP

  • Indication: all patients with suspected HF
  • Uses: to help confirm the diagnosis and assess disease severity and prognosis [1][21]
  • Interpretation

Normal BNP or NT-proBNP levels do not exclude HF. Always consider the complete clinical picture. [1][20]

Additional laboratory studies

Order the following studies to assess for causes of HF, comorbidities, and suitability for pharmacological treatment.

Most patients with HF (> 85%) have two or more associated chronic conditions. [1]

Transthoracic echocardiogram (TTE) [1][20]

Chest x-ray [1]

12-lead ECG [1][30][31]

Additional assessment [1][2]

Clinical composite scores

Advanced studies

The following studies may be ordered by a specialist if there is diagnostic uncertainty and/or to evaluate for underlying causes.

Identifying the specific cause of HF is crucial because it allows for tailored treatment in addition to GDMT. [1]

Pathologytoggle arrow icon

Sputum analysis in patients with pulmonary edema may show heart failure cells (hemosiderin-containing cells).

Differential diagnosestoggle arrow icon

Managementtoggle arrow icon

Management of AHF is detailed in “Acute HF.”

Approach [1][2]

Multidisciplinary management of HF that includes nurses, cardiologists, and clinical pharmacists is associated with lower hospitalization and mortality rates. [1][2]

Nonpharmacological interventions [1][20]

Encourage and/or provide the following in combination with pharmacotherapy for HF.

Nonpharmacological interventions are associated with better patient outcomes, e.g., decreased rates of hospitalization and all-cause and cardiovascular mortality. [1]

Management of comorbidities [1][2]

The following recommendations are specific to comorbidities in HF. Treat other comorbidities (e.g., lipid disorders, ASCVD, atrial fibrillation) as recommended by guidelines.

Monitoring [1][2]

To optimize GDMT, the following factors should be assessed at each patient visit.

Pharmacotherapytoggle arrow icon

General principles [1][2]

Pharmacotherapy for HFrEF [1][3]

Initial pharmacotherapy for HFrEF [1][3]
Class Indications Recommended agents
Diuretics Loop diuretics
  • Preferred option for all patients with congestion
Thiazide diuretics
RAAS inhibitors Angiotensin receptor-neprilysin inhibitors (ARNIs)
  • All patients with ACC/AHA stages C and D HFrEF (preferred initial agent for RAAS inhibition) [1]
  • For patients already prescribed an ACEI, stop ACEIs 36 hours before starting an ARNI to avoid an elevated risk of angioedema.

ACE inhibitors (ACEIs)

  • All patients with ACC/AHA stage B HFrEF
  • Patients with ACC/AHA stages C and D HFrEF if ARNI is not tolerated or affordable
Angiotensin receptor blockers (ARBs)
  • Patients with ACC/AHA stages B, C, and D HFrEF if ARNI and ACEIs are not tolerated (e.g., because of a dry cough or history of angioedema) or affordable
Beta blockers
  • All patients with ACC/AHA stages B, C, and D HFrEF
SGLT2 inhibitors (SGLT2is)
  • All patients with ACC/AHA stage C HFrEF
Mineralocorticoid receptor antagonists (MRAs)
  • All patients with ACC/AHA stage C HFrEF without contraindications i.e., eGFR < 30 mL/min/1.73 m2 and serum K+ > 5.0 mEq/L

Drugs that improve prognosis (i.e., reduce morbidity, mortality, and hospitalization rates) are beta blockers, ACEIs, ARNIs, MRAs, hydralazine with isosorbide dinitrate, and SGLT2is.

Additional pharmacotherapy for HFrEF [1][3]
Class Indications Recommended agents
Isosorbide dinitrate with hydralazine
  • Add to first-line therapy for African American patients with NYHA III–IV HFrEF [1]
  • May be considered in patients who cannot tolerate ARNI, ACEIs, or ARBs (e.g., due to impaired kidney function) [1]
If channel inhibitor
  • Refractory symptoms despite first-line GDMT [1]
Soluble guanylate cyclase stimulator
  • Vericiguat
Omega-3 fatty acid
  • May be added to first-line GDMT in patients with NYHA II–IV HFrEF

Diuretics and digoxin improve symptoms and significantly reduce the number of hospitalizations.

Pharmacotherapy for HFpEF [2][3][20]

Drugs that may worsen HF [1]

The following drugs should be avoided or used with caution in patients with HF.

Device therapy and advanced HF managementtoggle arrow icon

Device therapy in HF

Automated implantable cardioverter defibrillators (AICDs) and cardiac resynchronization therapy devices (CRTs) are beneficial in select patients with HF who are at risk for sudden cardiac death from ventricular tachyarrhythmias and who have worsening HF from cardiac dyssynchrony. [1][40]

AICDs in heart failure [1]

For more information, see “AICDs.”

CRT in heart failure [1]

For more information, see “CRTs.”

  • Goal consists of synchronizing contractions of the right and left ventricles, resulting in:
  • Indications: The following criteria apply to patients with stage C HFrEF on optimized medical therapy and an expected survival of > 1 year.
    • LVEF ≤ 35% with NYHA class II–IV symptoms and sinus rhythm OR select patients with AFib PLUS:
      • QRS duration of > 150 ms with or without LBBB pattern
      • OR QRS duration of 120–149 ms with LBBB pattern
    • LVEF ≤ 35% requiring pacing for other purposes, e.g., replacement of existing PPM
    • LVEF 36–50% with high-risk AV block

Consider CRT-D in patients with indications for both CRT and AICD.

Advanced heart failure management (ACC/AHA stage D) [1][3]

Promptly refer all patients with advanced HF to an HF specialist for management.

Complicationstoggle arrow icon

We list the most important complications. The selection is not exhaustive.

Cardiorenal syndrometoggle arrow icon

Prognosistoggle arrow icon

The prognosis depends on the patient, type and severity of heart disease, and adherence to GDMT and nonpharmacological interventions. Risk stratification scales may be used to determine prognosis (e.g., CHARM and CORONA risk scores).

Related One-Minute Telegramtoggle arrow icon

Interested in the newest medical research, distilled down to just one minute? Sign up for the One-Minute Telegram in “Tips and links” below.

Referencestoggle arrow icon

  1. $Heart Disease and Stroke Statistics—2020 Update: A Report From the American Heart Association.
  2. Lewsey SC, Breathett K. Racial and ethnic disparities in heart failure: current state and future directions. Curr Opin Cardiol. 2021; 36 (3): p.320-328.doi: 10.1097/hco.0000000000000855 . | Open in Read by QxMD
  3. Díez-Villanueva P, Jiménez-Méndez C, Alfonso F. Heart failure in the elderly.. JGC. 2021; 18 (3): p.219-232.doi: 10.11909/j.issn.1671-5411.2021.03.009 . | Open in Read by QxMD
  4. Heidenreich PA, Bozkurt B, Aguilar D, et al. 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. Circulation. 2022; 145 (18).doi: 10.1161/cir.0000000000001063 . | Open in Read by QxMD
  5. Murphy SP, Ibrahim NE, Januzzi JL. Heart Failure With Reduced Ejection Fraction. JAMA. 2020; 324 (5): p.488.doi: 10.1001/jama.2020.10262 . | Open in Read by QxMD
  6. Silverberg D, Wexler D, Blum M, Schwartz D, Iaina A. The association between congestive heart failure and chronic renal disease. Curr Opin Nephrol Hypertens. 2004; 13 (2): p.163-170.doi: 10.1097/00041552-200403000-00004 . | Open in Read by QxMD
  7. Kittleson MM, Panjrath GS, Amancherla K, et al. 2023 ACC Expert Consensus Decision Pathway on Management of Heart Failure With Preserved Ejection Fraction. J Am Coll Cardiol. 2023; 81 (18): p.1835-1878.doi: 10.1016/j.jacc.2023.03.393 . | Open in Read by QxMD
  8. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Chapter 183: Nocturia. . Accessed: June 19, 2019.
  9. Okoshi MP, Capalbo RV, Romeiro FG, Okoshi K. Cardiac Cachexia: Perspectives for Prevention and Treatment. Arq Bras Cardiol. 2016.doi: 10.5935/abc.20160142 . | Open in Read by QxMD
  10. Kasper DL, Fauci AS, Hauser S, Longo D, Jameson LJ, Loscalzo J . Harrisons Principles of Internal Medicine . McGraw-Hill Medical Publishing Division ; 2016
  11. Colucci WS. Evaluation of the patient with suspected heart failure. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. Last updated: October 19, 2015. Accessed: February 15, 2017.
  12. Redfield MM, Borlaug BA. Heart Failure With Preserved Ejection Fraction. JAMA. 2023; 329 (10): p.827.doi: 10.1001/jama.2023.2020 . | Open in Read by QxMD
  13. Tsutsui H, ALBERT NM, COATS AJS, et al. Natriuretic Peptides: Role in the Diagnosis and Management of Heart Failure: A Scientific Statement From the Heart Failure Association of the European Society of Cardiology, Heart Failure Society of America and Japanese Heart Failure Society. J Card Fail. 2023; 29 (5): p.787-804.doi: 10.1016/j.cardfail.2023.02.009 . | Open in Read by QxMD
  14. Filippatos TD. Hyponatremia in patients with heart failure. World J Cardiol. 2013; 5 (9): p.317.doi: 10.4330/wjc.v5.i9.317 . | Open in Read by QxMD
  15. Anand IS, Gupta P. Anemia and Iron Deficiency in Heart Failure. Circulation. 2018; 138 (1): p.80-98.doi: 10.1161/circulationaha.118.030099 . | Open in Read by QxMD
  16. Yancy CW, Jessup M, Bozkurt B, et al. 2017 ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guideline for the Management of Heart Failure: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Failure Society of America. Circulation. 2017; 136 (6).doi: 10.1161/cir.0000000000000509 . | Open in Read by QxMD
  17. Hudson MP, O’Connor CM, Gattis WA, et al. Implications of elevated cardiac troponin t in ambulatory patients with heart failure: a prospective analysis. Am Heart J. 2004; 147 (3): p.546-552.doi: 10.1016/j.ahj.2003.10.014 . | Open in Read by QxMD
  18. Wettersten N, Maisel A. Role of Cardiac Troponin Levels in Acute Heart Failure. Card Fail Rev. 2015; 1 (2): p.102.doi: 10.15420/cfr.2015.1.2.102 . | Open in Read by QxMD
  19. Omar AMS, Bansal M, Sengupta PP. Advances in Echocardiographic Imaging in Heart Failure With Reduced and Preserved Ejection Fraction. Circ Res. 2016; 119 (2): p.357-374.doi: 10.1161/circresaha.116.309128 . | Open in Read by QxMD
  20. Natanzon A, Kronzon I. Pericardial and Pleural Effusions in Congestive Heart Failure—Anatomical, Pathophysiologic, and Clinical Considerations. Am J Med Sci. 2009; 338 (3): p.211-216.doi: 10.1097/maj.0b013e3181a3936f . | Open in Read by QxMD
  21. Petrie MC, McMurray JJV. It cannot be cardiac failure because the heart is not enlarged on the chest X-ray. Eur J Heart Fail. 2003; 5 (2): p.117-119.doi: 10.1016/s1388-9842(02)00239-8 . | Open in Read by QxMD
  22. Zipes DP. Braunwald's Heart Disease. Mosby ; 2018
  23. Gouda P, Brown P, Rowe BH, McAlister FA, Ezekowitz JA. Insights into the importance of the electrocardiogram in patients with acute heart failure. Eur J Heart Fail. 2016; 18 (8): p.1032-1040.doi: 10.1002/ejhf.561 . | Open in Read by QxMD
  24. O’Neal WT, Mazur M, Bertoni AG, et al. Electrocardiographic Predictors of Heart Failure With Reduced Versus Preserved Ejection Fraction: The Multi‐Ethnic Study of Atherosclerosis. Journal of the American Heart Association. 2017; 6 (6).doi: 10.1161/jaha.117.006023 . | Open in Read by QxMD
  25. Davey PP, Barlow C, Hart G. Prolongation of the QT interval in heart failure occurs at low but not at high heart rates.. Clin Sci (Lond). 2000; 98 (5): p.603-10.
  26. Leyva F, Zegard A, Acquaye E, et al. Outcomes of Cardiac Resynchronization Therapy With or Without Defibrillation in Patients With Nonischemic Cardiomyopathy. J Am Coll Cardiol. 2017; 70 (10): p.1216-1227.doi: 10.1016/j.jacc.2017.07.712 . | Open in Read by QxMD
  27. Yancy CW, Jessup M, Bozkurt B, et al. 2013 ACCF/AHA Guideline for the Management of Heart Failure. J Am Coll Cardiol. 2013; 62 (16): p.e147-e239.doi: 10.1016/j.jacc.2013.05.019 . | Open in Read by QxMD
  28. Brignole M, Auricchio A, Baron-Esquivias G, Bordachar P et al. 2013 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy. Eur Heart J. 2013; 34 (29): p.2281-2329.doi: 10.1093/eurheartj/eht150 . | Open in Read by QxMD
  29. McDonagh TA, Metra M, Adamo M, et al. 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure. Eur Heart J. 2021; 42 (36): p.3599-3726.doi: 10.1093/eurheartj/ehab368 . | Open in Read by QxMD
  30. Mechanical Circulatory Support in a Nutshell. Updated: November 13, 2015. Accessed: October 22, 2020.
  31. Solomon SD, McMurray JJV, Claggett B, et al. Dapagliflozin in Heart Failure with Mildly Reduced or Preserved Ejection Fraction. N Engl J Med. 2022; 387 (12): p.1089-1098.doi: 10.1056/nejmoa2206286 . | Open in Read by QxMD
  32. Diagnosis of Abnormal Uterine Bleeding in Reproductive-Aged Women. Updated: July 1, 2012. Accessed: September 15, 2022.
  33. McDonagh TA, Metra M, Adamo M, et al. 2023 Focused Update of the 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure. Eur Heart J. 2023.doi: 10.1093/eurheartj/ehad195 . | Open in Read by QxMD
  34. Guck TP, Elsasser GN, Kavan MG, Eugene J. EJ. Depression and Congestive Heart Failure. Congest Heart Fail. 2003; 9 (3): p.163-169.doi: 10.1111/j.1527-5299.2003.01356.x . | Open in Read by QxMD
  35. Mehra MR, Park MH, Landzberg MJ, Lala A, Waxman AB. Right Heart Failure: Toward a Common Language. Pulm Circ. 2013; 3 (4): p.963-967.doi: 10.1086/674750 . | Open in Read by QxMD
  36. Kurmani S, Squire I. Acute Heart Failure: Definition, Classification and Epidemiology. Curr Heart Fail Rep. 2017; 14 (5): p.385-392.doi: 10.1007/s11897-017-0351-y . | Open in Read by QxMD
  37. Federmann M, Hess OM. Differentiation between Systolic and Diastolic Dysfunction. Eur Heart J. 1994; 15 (suppl D): p.2-6.doi: 10.1093/eurheartj/15.suppl_d.2 . | Open in Read by QxMD
  38. Borlaug BA, Redfield MM. Diastolic and Systolic Heart Failure Are Distinct Phenotypes Within the Heart Failure Spectrum. Circulation. 2011; 123 (18): p.2006-2014.doi: 10.1161/circulationaha.110.954388 . | Open in Read by QxMD
  39. Loscalzo J, Fauci AS, Kasper DL, Hauser SL, Longo D, Jameson JL. Harrison's Principles of Internal Medicine, Twenty-First Edition (Vol.1 & Vol.2). McGraw-Hill Education / Medical ; 2022
  40. Aronson D. Cardiorenal syndrome in acute decompensated heart failure. Expert Rev Cardiovasc Ther. 2014; 10 (2): p.177-189.doi: 10.1586/erc.11.193 . | Open in Read by QxMD
  41. Rangaswami J, Bhalla V, Blair JEA, et al. Cardiorenal Syndrome: Classification, Pathophysiology, Diagnosis, and Treatment Strategies: A Scientific Statement From the American Heart Association. Circulation. 2019; 139 (16).doi: 10.1161/cir.0000000000000664 . | Open in Read by QxMD
  42. Mahon NG, Blackstone EH, Francis GS, Starling RC, Young JB, Lauer MS. The prognostic value of estimated creatinine clearance alongside functional capacity in ambulatory patients with chronic congestive heart failure. J Am Coll Cardiol. 2002; 40 (6): p.1106-1113.doi: 10.1016/s0735-1097(02)02125-3 . | Open in Read by QxMD
  43. Whelton, PK, Carey, RM et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults. Hypertension. 2017; 71 (6): p.e13–e115.doi: 10.1161/hyp.0000000000000065 . | Open in Read by QxMD
  44. Kosiborod MN, Abildstrøm SZ, Borlaug BA, et al. Semaglutide in Patients with Heart Failure with Preserved Ejection Fraction and Obesity. N Engl J Med. 2023.doi: 10.1056/nejmoa2306963 . | Open in Read by QxMD
  45. Givertz MM, Haghighat A. High-output heart failure. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. Last updated: August 9, 2016. Accessed: February 24, 2017.
  46. Editors: Donald W Kufe, MD, Raphael E Pollock, MD, PhD, Ralph R Weichselbaum, MD, Robert C Bast, Jr, MD, Ted S Gansler, MD, MBA, James F Holland, MD, ScD (hc), and Emil Frei, III, MD. Holland-Frei Cancer Medicine. BC Decker ; 2003
  47. Long B, Koyfman A, Gottlieb M. Management of Heart Failure in the Emergency Department Setting: An Evidence-Based Review of the Literature. J Emerg Med. 2018; 55 (5): p.635-646.doi: 10.1016/j.jemermed.2018.08.002 . | Open in Read by QxMD
  48. Yancy CW, Jessup M, Bozkurt B, et al. 2013 ACCF/AHA Guideline for the Management of Heart Failure: Executive Summary. J Am Coll Cardiol. 2013; 62 (16): p.1495-1539.doi: 10.1016/j.jacc.2013.05.020 . | Open in Read by QxMD
  49. Van Diepen S, Katz JN, Albert NM, et al. Contemporary Management of Cardiogenic Shock: A Scientific Statement From the American Heart Association. Circulation. 2017; 136 (16).doi: 10.1161/cir.0000000000000525 . | Open in Read by QxMD
  50. Felker GM, Lee KL, Bull DA, et al. Diuretic Strategies in Patients with Acute Decompensated Heart Failure. N Engl J Med. 2011; 364 (9): p.797-805.doi: 10.1056/nejmoa1005419 . | Open in Read by QxMD
  51. Page RL, Joglar JA, Caldwell MA, et al. 2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia. Circulation. 2016; 133 (14): p.e506–e574.doi: 10.1161/cir.0000000000000311 . | Open in Read by QxMD
  52. January CT, Wann LS, Alpert JS, et al. 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation. J Am Coll Cardiol. 2014; 64 (21): p.e1-e76.doi: 10.1016/j.jacc.2014.03.022 . | Open in Read by QxMD
  53. Schünemann HJ, Cushman M, Burnett AE, et al. American Society of Hematology 2018 guidelines for management of venous thromboembolism: prophylaxis for hospitalized and nonhospitalized medical patients. Blood Advances. 2018; 2 (22): p.3198-3225.doi: 10.1182/bloodadvances.2018022954 . | Open in Read by QxMD
  54. Ivabradine. Updated: January 20, 2020. Accessed: March 26, 2020.
  55. Morales-Rull JL, Bielsa S, Conde-Martel A, et al. Pleural effusions in acute decompensated heart failure: Prevalence and prognostic implications. Eur J Intern Med. 2018; 52: p.49-53.doi: 10.1016/j.ejim.2018.02.004 . | Open in Read by QxMD
  56. Mercer RM, Corcoran JP, Porcel JM, Rahman NM, Psallidas I. Interpreting pleural fluid results. Clin Med (Northfield Il). 2019; 19 (3): p.213-217.doi: 10.7861/clinmedicine.19-3-213 . | Open in Read by QxMD

Icon of a lock3 free articles remaining

You have 3 free member-only articles left this month. Sign up and get unlimited access.
 Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer