Left-sided heart failure

1. Concept

Left-sided heart failure (LHF) occurs when the left ventricle loses its ability to pump oxygenated blood from the lungs to the body. Pressure backs up into the pulmonary circulation → pulmonary congestion.

2. Two physiological types

	Systolic (HFrEF)	Diastolic (HFpEF)
Defect	LV cannot contract forcefully (↓ ejection fraction)	LV stiff/thick, cannot fill properly (preserved EF)
LV wall	Weaker, thinner, dilated	Stiff/thickened
Result	↓ forward output, backward congestion	↓ filling → ↓ output

3. Causes

• Coronary artery disease / myocardial infarction (loss of contractile muscle).
• Valvular disease.
• Hypertension — LV works against ↑afterload → hypertrophy → loss of elasticity → eventual pump failure.

Hypertrophy patterns:

• Concentric — pressure overload (HTN, aortic stenosis): ↑wall thickness, ↓cavity.
• Eccentric — volume overload (aortic/mitral insufficiency): dilation, cavity enlargement, normal relative wall thickness.

4. Clinical features

• Pulmonary congestion: dyspnea (exertional, orthopnea, PND), cough.
• Peripheral edema, fatigue; over time → cardiomegaly, arrhythmia, cardiogenic shock.
• Diagnosis: ECG, echocardiogram (EF), coronary angiography, cardiac MRI.
• Treatment: ACE inhibitors (vasodilation/remodeling), aldosterone antagonists, beta-blockers, digoxin.

💡 High-yield: LHF → pulmonary congestion (dyspnea, orthopnea, PND, cough). Systolic = HFrEF (↓EF, dilated/thin LV) vs diastolic = HFpEF (stiff LV, preserved EF). Causes: CAD/MI, HTN, valvular. Concentric hypertrophy = pressure overload (HTN/AS); eccentric = volume overload. Treat with ACE-I, beta-blockers, aldosterone antagonists.