Heart failure

Definition

Heart failure (HF) is a clinical syndrome in which the heart is unable to pump blood sufficiently to meet the body’s metabolic needs or can do so only at elevated filling pressures. It results from structural or functional cardiac abnormalities that impair ventricular filling or ejection of blood.

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Classification

1. Based on Ejection Fraction (EF)

• Heart failure with reduced EF (HFrEF): EF ≤40%

• Heart failure with preserved EF (HFpEF): EF ≥50%

• Heart failure with mildly reduced EF (HFmrEF): EF 41–49%

2. Based on Onset

• Acute HF: Rapid onset of symptoms/signs (e.g., acute pulmonary edema)

• Chronic HF: Long-standing, stable or slowly progressive symptoms

3. Based on Clinical Presentation

• Left-sided HF: Pulmonary congestion and reduced systemic perfusion

• Right-sided HF: Systemic venous congestion (peripheral edema, hepatomegaly)

• Biventricular HF: Involvement of both ventricles

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Etiology

Cardiac causes

• Coronary artery disease (including myocardial infarction)

• Hypertension

• Cardiomyopathies (dilated, hypertrophic, restrictive)

• Valvular heart disease

• Arrhythmias (atrial fibrillation, tachycardia-induced cardiomyopathy)

• Congenital heart disease

Non-cardiac contributors

• Anemia

• Thyroid disorders (hyperthyroidism, hypothyroidism)

• Renal dysfunction

• Pulmonary diseases (COPD, pulmonary hypertension)

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Pathophysiology

HF involves one or both of:

• Systolic dysfunction: Impaired myocardial contractility → reduced stroke volume and EF

• Diastolic dysfunction: Impaired ventricular relaxation → reduced filling and preserved EF

Neurohormonal activation (renin–angiotensin–aldosterone system [RAAS], sympathetic nervous system) initially compensates for low cardiac output but ultimately worsens HF by promoting vasoconstriction, sodium/water retention, and myocardial remodeling.

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Clinical Features

Symptoms

• Dyspnea (exertional, orthopnea, paroxysmal nocturnal dyspnea)

• Fatigue, reduced exercise tolerance

• Swelling in legs, ankles, abdomen

• Nocturnal cough, weight gain from fluid retention

Signs

• Elevated jugular venous pressure (JVP)

• Pulmonary crackles

• Peripheral edema

• Hepatomegaly, ascites

• Displaced apex beat, S3 gallop

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Diagnosis

History and examination – Essential to suspect HF

Investigations:

• Blood tests: BNP or NT-proBNP (elevated in HF), CBC, renal function, electrolytes, thyroid function

• Chest X-ray: Pulmonary congestion, cardiomegaly

• ECG: Arrhythmias, ischemia, hypertrophy

• Echocardiography: Key for assessing EF, chamber size, wall motion, valvular function

• Additional tests: Cardiac MRI, coronary angiography (if ischemia suspected)

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Management

Goals: Relieve symptoms, improve quality of life, slow disease progression, reduce hospitalizations and mortality.

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1. General and Lifestyle Measures

• Fluid restriction (especially in hyponatremia)

• Sodium restriction (<2 g/day in some patients)

• Daily weight monitoring to detect fluid retention early

• Regular exercise as tolerated

• Smoking cessation, limit alcohol

• Vaccinations (influenza, pneumococcal)

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2. Pharmacological Treatment

A. HFrEF (EF ≤40%) – Guideline-Directed Medical Therapy

Core agents:

1. Angiotensin-converting enzyme (ACE) inhibitors – first-line

   • Enalapril: Start 2.5 mg orally twice daily → target 10–20 mg twice daily

   • Lisinopril: Start 2.5–5 mg once daily → target 20–40 mg once daily

2. Beta-blockers (only evidence-based ones: bisoprolol, carvedilol, metoprolol succinate)

   • Bisoprolol: Start 1.25 mg once daily → target 10 mg once daily

   • Carvedilol: Start 3.125 mg twice daily → target 25 mg twice daily (≤85 kg) or 50 mg twice daily (>85 kg)

3. Mineralocorticoid receptor antagonists (MRAs)

   • Spironolactone: Start 12.5–25 mg once daily → target 25–50 mg once daily

   • Eplerenone: Start 25 mg once daily → target 50 mg once daily

4. ARNI (angiotensin receptor–neprilysin inhibitor) – preferred over ACEI if tolerated

   • Sacubitril/valsartan: Start 49/51 mg twice daily → target 97/103 mg twice daily

   • Stop ACEI at least 36 hours before starting ARNI

Additional agents for selected patients:

• SGLT2 inhibitors: Dapagliflozin 10 mg daily or Empagliflozin 10 mg daily (benefit in HFrEF regardless of diabetes)

• Loop diuretics for fluid overload (symptom relief only): Furosemide 20–40 mg once or twice daily; titrate to maintain euvolemia

• Ivabradine if sinus rhythm, HR ≥70 bpm despite beta-blocker

• Hydralazine + isosorbide dinitrate for African descent patients or those intolerant to ACEI/ARB/ARNI

• Digoxin for symptomatic relief in selected patients (esp. with atrial fibrillation)

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B. HFpEF (EF ≥50%)

• No therapy proven to reduce mortality

• Manage comorbidities (hypertension, atrial fibrillation, diabetes)

• Use diuretics for symptom control from fluid overload

• Consider SGLT2 inhibitors (emerging evidence)

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3. Device Therapy

• Implantable cardioverter-defibrillator (ICD): For primary or secondary prevention of sudden cardiac death in HFrEF with EF ≤35% despite optimal therapy

• Cardiac resynchronization therapy (CRT): For symptomatic patients with EF ≤35%, sinus rhythm, LBBB with QRS ≥150 ms despite optimal therapy

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4. Advanced and Surgical Therapies

• Left ventricular assist devices (LVADs) as bridge to transplant or destination therapy

• Heart transplantation for eligible patients with end-stage HF

• Palliative care for advanced cases not suitable for aggressive interventions

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Complications

• Arrhythmias (atrial fibrillation, ventricular tachycardia)

• Thromboembolism

• Progressive renal dysfunction

• Recurrent hospitalizations

• Sudden cardiac death

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Prognosis

• Variable; depends on etiology, EF, comorbidities, and response to therapy

• HFrEF has improved outcomes with modern therapy, but mortality remains significant

• HFpEF prognosis similar to HFrEF but with fewer treatment options