Definition

Heart failure is a clinical syndrome characterized by the inability of the heart to pump blood efficiently to meet the body’s metabolic demands. It results from structural or functional impairment of ventricular filling or ejection, leading to symptoms such as dyspnea, fatigue, and fluid retention.

Classification of Heart Failure

Heart failure can be classified based on different criteria:

1. Based on Ejection Fraction (EF)

• Heart Failure with Reduced Ejection Fraction (HFrEF): EF ≤40%
• Heart Failure with Mid-Range Ejection Fraction (HFmrEF): EF 41-49%
• Heart Failure with Preserved Ejection Fraction (HFpEF): EF ≥50%

2. Based on Clinical Presentation

• Acute Heart Failure: Sudden onset or worsening of symptoms, often requiring emergency care
• Chronic Heart Failure: Progressive condition with long-term symptoms and compensatory mechanisms

3. Based on Affected Cardiac Side

• Left-Sided Heart Failure: Affects the left ventricle, causing pulmonary congestion
• Right-Sided Heart Failure: Affects the right ventricle, leading to systemic venous congestion
• Biventricular Heart Failure: Both ventricles are involved

4. Based on Circulatory Pathophysiology

• Forward Failure: Reduced cardiac output leads to poor organ perfusion
• Backward Failure: Blood backs up into venous circulation, leading to congestion

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Epidemiology

• Prevalence: Affects approximately 1-2% of the global adult population, with higher rates in older individuals (>10% in those over 70 years).
• Risk Factors:
  • Hypertension
  • Coronary artery disease
  • Diabetes mellitus
  • Valvular heart disease
  • Cardiomyopathies
  • Chronic kidney disease

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Symptoms and Signs of Heart Failure

1. Typical Symptoms

• Dyspnea: Shortness of breath, especially on exertion
• Fatigue and Weakness
• Exercise Intolerance: Reduced ability to perform physical activities
• Peripheral Edema: Fluid retention, particularly in lower limbs
• Nocturnal Symptoms:
  • Orthopnea (dyspnea when lying flat)
  • Paroxysmal nocturnal dyspnea (sudden nighttime breathlessness)
  • Nocturia (frequent nighttime urination)

2. Additional Symptoms

• Cardiac Symptoms: Palpitations, sinus tachycardia, arrhythmias, syncope
• Respiratory Symptoms: Wheezing (cardiac asthma), pleural effusion
• Gastrointestinal Symptoms: Loss of appetite, bloating, nausea, right upper quadrant pain (hepatic congestion)
• Neurological Symptoms: Dizziness, confusion, depression, Cheyne-Stokes respiration
• Skin Symptoms: Cold extremities, pallor, cyanosis (advanced cases)

3. Signs on Physical Examination

• Pulmonary Congestion: Crackles, wheezing, pleural effusion
• Jugular Venous Distension: Due to increased central venous pressure
• Hepatojugular Reflux: Sign of right-sided failure
• Peripheral Edema: Pitting edema in lower extremities
• Ascites: Fluid accumulation in the abdomen (advanced right heart failure)

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Diagnosis of Heart Failure

1. Clinical Assessment

• Detailed history and physical examination to identify risk factors and symptoms

2. Laboratory Tests

• Natriuretic Peptides (BNP/NT-proBNP): Elevated in heart failure
• Kidney Function Tests: Assess renal impairment
• Liver Enzymes: Elevated in right-sided failure
• Electrolytes: Monitor potassium and sodium levels
• Thyroid Function Tests: Rule out secondary causes

3. Imaging and Functional Tests

• Echocardiography: Gold standard to assess ventricular function, ejection fraction, and valvular abnormalities
• Chest X-ray: Detects pulmonary congestion, cardiomegaly, pleural effusion
• ECG: Identifies arrhythmias, ischemic changes, or left ventricular hypertrophy
• Cardiac MRI: Used in specific cases to assess myocardial structure
• Coronary Angiography: Performed if ischemic heart disease is suspected

4. Functional Classification

• New York Heart Association (NYHA) Classification:
  • Class I: No limitation in physical activity
  • Class II: Mild limitation; comfortable at rest but symptoms with exertion
  • Class III: Marked limitation; symptoms with minimal activity
  • Class IV: Severe limitation; symptoms at rest

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Therapy for Heart Failure

1. Lifestyle and Non-Pharmacological Measures

• Sodium Restriction: Reduces fluid retention
• Fluid Management: Limits daily fluid intake in severe cases
• Weight Monitoring: Detects early fluid accumulation
• Regular Exercise: Improves functional capacity
• Smoking and Alcohol Cessation

2. Pharmacological Therapy

• First-Line Medications (HFrEF)

  • ACE Inhibitors / ARBs/ARNI: Reduce afterload and improve survival
  • Beta-Blockers: Lower heart rate, reduce mortality
  • Mineralocorticoid Receptor Antagonists (MRAs): E.g., Spironolactone
  • SGLT2 Inhibitors: Newer class improving outcomes in HFrEF and HFpEF

• Diuretics: For fluid overload, but do not improve survival

• Ivabradine: For patients with high heart rates despite beta-blockers

• Digoxin: Used in refractory cases or atrial fibrillation with heart failure

3. Device Therapy

• Implantable Cardioverter Defibrillator (ICD): Prevents sudden cardiac death
• Cardiac Resynchronization Therapy (CRT): Improves ventricular function in select cases
• Mechanical Circulatory Support (LVADs): For end-stage heart failure

4. Surgical Options

• Coronary Artery Bypass Grafting (CABG): If ischemic heart disease is the cause
• Heart Transplantation: In refractory end-stage heart failure