Heart failure

 

 

Definition

Heart failure (HF) is a complex clinical syndrome in which the heart is unable to pump sufficient blood to meet the metabolic demands of the body, or can do so only at the expense of elevated filling pressures. It is not a single disease but the final common pathway of many cardiac disorders.

Classification of Heart Failure

1. Based on Ejection Fraction (EF)

• HFrEF (Heart Failure with Reduced EF)
  EF < 40%
  → Systolic dysfunction (impaired contraction)
• HFmrEF (Mildly Reduced EF)
  EF 41–49%
• HFpEF (Preserved EF)
  EF ≥ 50%
  → Diastolic dysfunction (impaired relaxation)

🔑 Exam pearl: HFrEF has strong evidence-based mortality-reducing therapies, HFpEF mainly focuses on symptom control and comorbidity management.

2. Based on Sidedness

• Left-sided HF → pulmonary congestion
• Right-sided HF → systemic venous congestion
• Biventricular HF → features of both

3. Based on Time Course

• Acute HF: sudden decompensation (e.g., MI, hypertensive crisis)
• Chronic HF: long-standing, compensated or decompensated

Etiology (Causes)

Common Causes of HFrEF

• Ischemic heart disease (most common)
• Hypertension
• Dilated cardiomyopathy
• Valvular heart disease
• Toxins (alcohol, chemotherapy)
• Myocarditis

Common Causes of HFpEF

• Long-standing hypertension
• Aging
• Obesity
• Diabetes mellitus
• Hypertrophic cardiomyopathy
• Restrictive cardiomyopathy

Pathophysiology

Heart failure is driven by two major mechanisms:

1. Reduced Cardiac Output

• ↓ Stroke volume → ↓ tissue perfusion
• Leads to fatigue, weakness, renal hypoperfusion

2. Neurohormonal Activation (Maladaptive)

The body compensates initially, but chronic activation worsens HF.

Major systems involved:

• Sympathetic nervous system
  
• ↑ Heart rate
• ↑ Contractility
• Vasoconstriction
• 
  
• Renin-Angiotensin-Aldosterone System (RAAS)
  
• Sodium and water retention
• Vasoconstriction
• Ventricular remodeling
• 
  
• ADH (Vasopressin)
  
• Free water retention → hyponatremia
• 
  

🔑 Key concept: What helps acutely harms chronically.

Clinical Manifestations

Symptoms

Left-sided HF

• Dyspnea on exertion
• Orthopnea
• Paroxysmal nocturnal dyspnea (PND)
• Cough, frothy sputum
• Fatigue

Right-sided HF

• Peripheral edema
• Abdominal distension
• Ascites
• Early satiety
• Weight gain

Signs

• Elevated JVP
• S3 gallop (HFrEF)
• S4 gallop (HFpEF)
• Pulmonary crackles
• Hepatomegaly
• Pitting edema
• Cool extremities (advanced HF)

Diagnosis

1. Laboratory Tests

• BNP / NT-proBNP
  
• Elevated in HF
• Helps differentiate HF from other causes of dyspnea
• 
  
• Electrolytes (Na⁺, K⁺)
• Renal function
• Liver enzymes
• Thyroid function

2. Imaging

Echocardiography (MOST IMPORTANT)

• EF assessment
• Chamber size
• Wall motion abnormalities
• Valvular disease
• Diastolic function

Chest X-ray

• Cardiomegaly
• Pulmonary edema
• Pleural effusion

3. ECG

• Ischemia
• LVH
• Arrhythmias (AF common)

Management of Heart Failure

General Measures

• Sodium restriction
• Fluid restriction (in advanced HF)
• Daily weight monitoring
• Vaccinations (influenza, pneumococcal)
• Exercise-based cardiac rehab

Pharmacologic Management of HFrEF (Cornerstone)

1. ARNI / ACEi / ARB

• Reduce mortality and morbidity
• Reverse remodeling

2. Beta-blockers (Evidence-based)

• Metoprolol succinate
• Carvedilol
• Bisoprolol

Start low, go slow

3. Mineralocorticoid Receptor Antagonists

• Spironolactone
• Eplerenone
• ↓ mortality

4. SGLT2 Inhibitors

• Dapagliflozin
• Empagliflozin
• Benefit with or without diabetes

5. Diuretics

• Loop diuretics (furosemide)
• Symptom relief only (no mortality benefit)

Additional Therapies

• Hydralazine + nitrates (African descent or ACEi intolerance)
• Ivabradine (high HR despite beta-blocker)
• Digoxin (symptom control, AF)

Management of HFpEF

• Control blood pressure
• Treat ischemia
• Manage atrial fibrillation
• Diuretics for congestion
• Weight loss and exercise
• Treat comorbidities (DM, OSA)

Acute Decompensated Heart Failure

Common Triggers

• Infection
• Non-compliance
• MI
• Arrhythmias
• Hypertensive crisis

Management

• Oxygen / NIV
• IV loop diuretics
• Vasodilators (if hypertensive)
• Inotropes (only in cardiogenic shock)

Complications

• Arrhythmias (AF, VT, VF)
• Thromboembolism
• Cardiorenal syndrome
• Cachexia
• Sudden cardiac death

Prognosis

Heart failure is a chronic progressive disease with high morbidity and mortality. Prognosis depends on:

• EF
• NYHA class
• Renal function
• Adherence to therapy

Key Exam Pearls 🧠

• S3 → systolic dysfunction
• HFpEF = stiff ventricle
• BNP normal → HF unlikely
• Diuretics improve symptoms, not survival
• Four pillars of HFrEF therapy