What are the causes, diagnosis, and treatment of Congestive Heart Failure (CHF)?

Congestive Heart Failure: Causes, Diagnosis, and Treatment

Congestive heart failure (CHF) is a syndrome resulting from cardiac dysfunction that leads to failure of the heart to deliver adequate oxygen to metabolizing tissues, causing symptoms like breathlessness, fatigue, and fluid retention that significantly impact morbidity, mortality, and quality of life. 1

Causes of CHF

• Coronary artery disease (CAD) is the most common cause, responsible for approximately two-thirds of systolic heart failure cases 1
• Hypertension, particularly systolic hypertension leading to myocardial hypertrophy and fibrosis 1
• Diabetes mellitus, often contributing alongside other risk factors 1
• Previous viral infections (recognized or unrecognized) 1
• Alcohol abuse 1
• Cardiotoxic medications (e.g., certain chemotherapeutic agents like doxorubicin or trastuzumab) 1
• Valvular heart disease 1, 2
• Cardiomyopathies (dilated, hypertrophic, restrictive) 2
• Myocarditis and other infections 2
• Systemic toxins 2

Diagnosis of CHF

Clinical Presentation

• Typical symptoms include:

  • Breathlessness (at rest or during exertion) 1
  • Fatigue 1
  • Ankle swelling 1
  • Orthopnea and paroxysmal nocturnal dyspnea (more specific but less common) 1

• Typical signs include:

  • Elevated jugular venous pressure 1
  • Pulmonary crackles 1
  • Displaced apex beat 1
  • Peripheral edema 1
  • Hepatomegaly 1

Diagnostic Criteria

For a definitive diagnosis of heart failure, the following must be satisfied:

1. Symptoms typical of heart failure
2. Objective evidence of cardiac dysfunction (systolic and/or diastolic) at rest
3. Response to treatment directed toward heart failure (in cases where diagnosis is in doubt) 1

Classification

• Heart failure with reduced ejection fraction (HF-REF): Symptoms and signs of HF with reduced LVEF 1
• Heart failure with preserved ejection fraction (HF-PEF): Symptoms and signs of HF with normal LVEF 1
• New York Heart Association (NYHA) functional classification:
  • Class I: No limitation of physical activity
  • Class II: Slight limitation of physical activity
  • Class III: Marked limitation of physical activity
  • Class IV: Unable to carry out any physical activity without discomfort 1

Diagnostic Investigations

• Electrocardiogram (ECG) 3
• Chest X-ray to assess for pulmonary congestion 3
• Echocardiography to determine:
  • Left ventricular ejection fraction
  • Chamber sizes
  • Wall thickness
  • Valve function 1
• Laboratory tests:
  • Renal function
  • Electrolytes
  • Complete blood count
  • Liver function tests
  • Thyroid function 1
• Natriuretic peptides (BNP or NT-proBNP) when diagnosis is uncertain 1

Treatment of CHF

Non-pharmacological Interventions

• Patient education about the condition, symptom recognition, and self-management 1
• Daily weight monitoring to detect fluid retention early 1
• Sodium restriction, particularly in advanced heart failure 1
• Fluid restriction (1.5-2 L/day) in advanced heart failure 1
• Regular physical activity and exercise training programs for stable NYHA II-III patients 1
• Alcohol moderation (1-2 glasses of wine/day permitted except in alcoholic cardiomyopathy) 1
• Smoking cessation 1

Pharmacological Treatment

First-line Therapy

• Angiotensin-converting enzyme (ACE) inhibitors are recommended as first-line therapy in all patients with reduced left ventricular systolic function (LVEF <40-45%), with or without symptoms 1

  • Should be uptitrated to doses shown effective in clinical trials 1
  • Improve survival and reduce hospitalization 4, 5

• Beta-blockers (particularly carvedilol, bisoprolol, metoprolol succinate) in stable patients 4, 5

  • Improve survival and reduce hospitalization
  • Should be initiated at low doses and gradually uptitrated

• Diuretics for symptomatic relief of fluid overload 1

  • Loop diuretics or thiazides for initial treatment 1
  • Essential when pulmonary congestion or peripheral edema is present 1
  • Should be administered in combination with ACE inhibitors when possible 1

• Mineralocorticoid receptor antagonists (MRAs) in select patients with NYHA class III-IV symptoms 1, 5

Additional Therapies

• Angiotensin receptor blockers (ARBs) when ACE inhibitors are not tolerated 5
• Hydralazine and isosorbide dinitrate combination, particularly in patients who cannot tolerate ACE inhibitors or ARBs 5
• Digoxin to improve clinical symptoms, especially in patients with atrial fibrillation 5
• Ivabradine for specific patients with elevated heart rate despite beta-blocker therapy 1

Devices and Surgical Interventions

• Cardiac resynchronization therapy (CRT) for patients with wide QRS complex 1
• Implantable cardioverter-defibrillator (ICD) for prevention of sudden cardiac death 1
• Coronary revascularization when ischemic heart disease is present 1
• Valve repair/replacement for significant valvular disease 1
• Ventricular assist devices for end-stage heart failure 1, 2
• Heart transplantation for selected patients with end-stage heart failure 1, 2

Monitoring and Follow-up

• Regular assessment of symptoms, signs, and functional capacity 1
• Monitoring of renal function, electrolytes, and blood pressure, particularly after medication changes 1
• Adjustment of therapy based on clinical response and tolerance 1
• Education about medication adherence and recognition of worsening symptoms 1

Pitfalls and Caveats

• Heart failure symptoms can be difficult to interpret, especially in elderly, obese patients, and women 1
• Signs of fluid retention may resolve quickly with diuretic therapy and may be absent in treated patients 1
• There is a poor relationship between symptoms and severity of cardiac dysfunction 1
• NSAIDs, certain calcium channel blockers (verapamil, diltiazem), and Class I antiarrhythmics should be avoided in heart failure patients 1
• Renal function should be monitored closely when initiating or uptitrating ACE inhibitors 1