What are the causes of heart failure?

Causes of Heart Failure

Heart failure is primarily caused by coronary artery disease, hypertension, and dilated cardiomyopathy, with valvular heart disease also being a common contributor. 1, 2

Major Etiologies

Cardiovascular Causes

• Coronary artery disease: The most common cause of heart failure, particularly in younger age groups 1, 2

  • Myocardial infarction leading to damaged heart muscle
  • Chronic ischemic heart disease causing progressive dysfunction

• Hypertension: Long-standing high blood pressure leads to:

  • Left ventricular hypertrophy
  • Increased afterload
  • Progressive myocardial dysfunction 1, 2

• Valvular heart disease:

  • Mitral regurgitation or stenosis
  • Aortic stenosis or regurgitation
  • Progressive annular dilatation leading to worsening regurgitation 1

• Cardiomyopathies:

  • Dilated cardiomyopathy (up to 30% may have genetic causes) 1
  • Hypertrophic cardiomyopathy
  • Restrictive cardiomyopathy
  • Arrhythmogenic right ventricular cardiomyopathy

Non-Cardiovascular Causes

• Infectious:

  • Myocarditis (especially viral)
  • Chagas disease 1

• Toxic exposures:

  • Alcohol abuse
  • Chemotherapeutic drugs (especially anthracyclines)
  • Illicit drugs
  • Mediastinal radiation 1

• Metabolic/Endocrine:

  • Diabetes mellitus (accelerates atherosclerosis and causes diabetic cardiomyopathy) 2
  • Thyroid disorders (both hypo- and hyperthyroidism)
  • Pheochromocytoma 1

• High-output states (causing heart failure despite normal or increased cardiac output):

  • Severe anemia
  • Thyrotoxicosis
  • Arteriovenous shunts
  • Sepsis
  • Beriberi
  • Paget's disease
  • Liver failure 1, 3

• Other causes:

  • Tachycardia-induced cardiomyopathy
  • Peripartum cardiomyopathy
  • Congenital heart defects
  • Sleep-disordered breathing 1

Pathophysiological Mechanisms

Heart failure develops through a complex cascade involving:

1. Initial myocardial injury or stress
2. Cardiac remodeling: Chamber dilatation, hypertrophy, and increased sphericity 1
3. Neurohormonal activation: Adrenergic and renin-angiotensin-aldosterone systems, endothelin, vasopressin, and inflammatory mediators 1
4. Hemodynamic consequences: Decreased cardiac output and increased filling pressures 2

Risk Factors and Special Considerations

• Age: Prevalence rises sharply after 75 years, reaching 10-20% in 70-80 year olds 1, 4
• Sex: More common in men at younger ages; equal prevalence in elderly 1, 2
• Comorbidities: Diabetes, obesity, kidney disease, and COPD can worsen heart failure progression 1

Clinical Pearls and Pitfalls

• Heart failure is a clinical syndrome, not equivalent to cardiomyopathy or left ventricular dysfunction 1
• Up to 40-50% of heart failure patients have preserved ejection fraction (HFpEF), particularly elderly, women, and those with hypertension or diabetes 1, 5
• The presence of multiple etiologies is common, especially in elderly patients 4
• High-output heart failure presents with similar symptoms but requires different management approaches than low-output heart failure 3
• Always consider potentially reversible causes (thyroid disease, alcohol, tachyarrhythmias) 1

Understanding the specific cause(s) of heart failure in each patient is crucial for appropriate management and potentially addressing reversible factors that can improve outcomes.