Heart Failure (HF) 💓

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💓 Heart Failure (HF) – High Yield Overview

Terminology

  • Congestive Heart Failure (CHF): HF with signs/symptoms of fluid overload

  • Left Heart Failure (LHF): Structural/functional impairment of left heart → tissue hypoperfusion & ↑ pulmonary capillary pressure

  • Right Heart Failure (RHF): Structural/functional impairment of right heart → impaired pulmonary blood flow & ↑ venous pressures

  • Biventricular (Global) HF: Both ventricles affected → combined RHF + LHF

Historical terms:

  • Systolic HF

  • Diastolic HF

Epidemiology

  • Incidence increases with age

  • ~20% of individuals >75 years are affected

  • Data mostly from the United States

Classification

By LVEF

  • HFrEF (≤ 40%) → reduced stroke volume & contractility

  • HFpEF (≥ 50%) → reduced filling, preserved EF

NYHA Functional Classification

ClassCharacteristics
INo limitation, no symptoms
IIMild symptoms with ordinary activity
IIIMarked limitation, symptoms with less-than-ordinary activity, comfortable only at rest
IVSevere limitation, symptoms at rest

Pathophysiology

  • Cardiac Output (CO) = Stroke Volume × HR

  • Controlled by preload, afterload, contractility

HFrEF (systolic dysfunction)

  • ↓ contractility → ↓ EF → ↓ CO

  • Causes: MI, CAD, dilated cardiomyopathy, arrhythmias

HFpEF (diastolic dysfunction)

  • ↓ compliance → impaired filling → ↑ diastolic pressure

  • EF preserved

  • Causes: HTN with LV hypertrophy, restrictive cardiomyopathy, tamponade

Forward vs Backward Failure

  • Forward: ↓ CO → poor organ perfusion (renal failure, fatigue)

  • Backward: venous congestion

    • LHF → pulmonary edema, orthopnea, PND

    • RHF → systemic congestion, edema, hepatomegaly, nutmeg liver



Compensatory Mechanisms

  • Sympathetic activation → tachycardia, ↑ contractility

  • RAAS activation

    • Angiotensin II → vasoconstriction (↑ afterload)

    • Aldosterone → Na⁺/H₂O retention (↑ preload)

  • BNP/NT-proBNP release → vasodilation, natriuresis (diagnostic biomarkers)

Clinical Features

General

  • Fatigue, nocturia

  • Tachycardia, arrhythmias

  • S3/S4 gallop, pulsus alternans

  • Cardiac cachexia

Left-Sided HF

  • Dyspnea, orthopnea, PND

  • Pulmonary edema (crackles, rales)

  • Cardiac asthma

  • Laterally displaced apical impulse

Right-Sided HF

  • Peripheral pitting edema

  • Jugular venous distention (JVD)

  • Hepatosplenomegaly, ascites

  • Hepatojugular reflux

  • Kussmaul sign

Subtypes / Variants

High-Output Heart Failure

  • Definition: HF despite ↑ cardiac output (cannot meet tissue demand)

  • Causes:

    • Physiological: pregnancy, fever, exercise

    • Pathological: anemia, hyperthyroidism, beriberi (B1 deficiency), cirrhosis, AV fistulas, Paget disease, obesity

  • Features: bounding pulses, S3 gallop, pulsatile tinnitus, low BP

Diagnosis

Lab Studies

  • BNP / NT-proBNP → elevated in HF

Imaging

  • Echo (TTE): gold standard – shows systolic or diastolic dysfunction


  • CXR: pulmonary congestion, cardiomegaly, pulmonary edema


Other

  • Right heart cath: ↓ SvO₂ in decompensated HF

Pathology

  • Heart failure cells: hemosiderin-laden macrophages in lungs (from pulmonary congestion)

  • Pulmonary alveolar edema

  • Nutmeg liver (chronic RHF)

Management

Non-Pharmacological

  • Lifestyle: weight loss, exercise, smoking/alcohol cessation

  • Nutrition: ↓ sodium, fluid restriction

Pharmacotherapy

HFrEF (Guideline-Directed Medical Therapy – GDMT)

ClassAgentsNotes
DiureticsLoop (furosemide, bumetanide, torsemide); add thiazide if resistantSymptom relief only
RAAS InhibitorsARNI (sacubitril/valsartan) – preferred
ACEIs (enalapril, lisinopril, ramipril)
ARBs (losartan, valsartan)		Stop ACEI 36h before ARNI
Beta BlockersCarvedilol, Metoprolol succinate, BisoprololImproves survival
SGLT2 inhibitorsDapagliflozin, EmpagliflozinFor all NYHA II–IV HFrEF
Mineralocorticoid antagonistsSpironolactone, EplerenoneAvoid if eGFR <30 or K⁺ >5

Additional Therapy:

  • Hydralazine + isosorbide dinitrate → African American NYHA III–IV

  • Ivabradine → HR ≥70 bpm despite max BB

  • Digoxin → refractory symptoms

  • Vericiguat → worsening HF despite GDMT

  • Omega-3 fatty acids → add-on option

Prognosis-improving drugs:
✔ Beta blockers
✔ ACEIs / ARNIs / ARBs
✔ MRAs
✔ SGLT2 inhibitors
✔ Hydralazine + isosorbide dinitrate


✅ High-Yield Takeaways:

  • BNP/NT-proBNP: diagnostic biomarkers

  • Echo: best imaging test

  • HFrEF GDMT improves survival

  • Watch for decompensation signs: pulmonary edema, ascites, arrhythmias

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