Heart Failure: Etiology, Classification, Stages, Pathophysiology, Pathology, and Complications

Introduction

Heart failure (HF) is a chronic condition in which the heart is unable to pump sufficient blood to meet the body’s demands. It results from structural or functional impairment and is classified into various types based on underlying causes and presentation.

Etiology of Heart Failure

• Coronary artery disease (CAD)
• Hypertension
• Cardiomyopathies
• Valvular heart disease
• Congenital heart defects

Classification of Heart Failure

Systolic vs. Diastolic Heart Failure

Systolic HF occurs due to reduced left ventricular ejection fraction (LVEF), leading to decreased cardiac output. Diastolic HF, or HF with preserved ejection fraction (HFpEF), results from impaired ventricular relaxation and increased filling pressures.

Left vs. Right Heart Failure

Left-sided HF primarily leads to pulmonary congestion, whereas right-sided HF results in systemic venous congestion, causing peripheral edema.

Stages of Heart Failure

1. Stage A: High risk for HF but no structural heart disease.
2. Stage B: Structural heart disease without symptoms.
3. Stage C: Structural heart disease with past or current symptoms.
4. Stage D: Refractory HF requiring specialized interventions.

Pathophysiology of Heart Failure

HF involves maladaptive mechanisms such as neurohormonal activation, ventricular remodeling, and increased cardiac workload. Elevated levels of norepinephrine, renin-angiotensin-aldosterone system (RAAS) activation, and inflammatory cytokines contribute to progression.

Pathology of Heart Failure

Histopathological changes include myocyte hypertrophy, interstitial fibrosis, and mitochondrial dysfunction. Autopsy findings often reveal cardiomegaly, pulmonary congestion, and systemic edema.

Complications of Heart Failure

• Pulmonary hypertension
• Arrhythmias
• Cardiogenic shock
• Renal dysfunction
• Thromboembolism

Conclusion

Heart failure remains a global health challenge requiring early diagnosis and comprehensive management to improve patient outcomes.