Cardiogenic Shock

 Cardiogenic Shock  

Etiology (Causes)

• Most common: Myocardial infarction (MI)

• Arrhythmias (severe bradycardia/tachycardia)

• Heart failure (acute decompensation)

• Cardiomyopathy (dilated, restrictive, hypertrophic)

• Myocarditis

• Structural defects:

  • Ventricular septal defect (post-MI)

  • Ventricular free wall rupture

  • Severe valve defects (mitral or aortic regurgitation)

• Blunt cardiac trauma

• Drugs: beta-blockers, calcium channel blockers (overdose or acute effects)

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Pathophysiology

1. Heart dysfunction → ↓ cardiac contractility & stroke volume → ↓ cardiac output (CO)

2. Systemic circulation:

   • ↓ CO & ↓ BP → ↑ catecholamines → vasoconstriction → ↑ myocardial oxygen demand

   • Activation of RAAS → further vasoconstriction & sodium/water retention

   • Blood shunted to vital organs → peripheral hypoperfusion

3. Pulmonary circulation:

   • ↑ pulmonary hydrostatic pressure → pulmonary edema

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Clinical Classification

Type	Hemodynamic / Clinical Features
Dry & Cold	No congestion, hypotensive, cold extremities
Wet & Cold	Evidence of congestion (pulmonary/systemic), hypotension, cold extremities

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Management Approach

General Principles:

• Elevate head, provide respiratory support if pulmonary congestion

• Stop/adjust medications worsening shock

• Treat underlying cause (e.g., MI → revascularization)

• Supportive care & hemodynamic monitoring

Treatment by Type:

Type	Initial Treatment	Notes / Escalation
Dry & Cold	- Fluid bolus if hypotensive or PCWP < 15 mmHg (250–500 mL, reassess) - Vasopressors if shock persists (norepinephrine preferred) - Inotropes if hypoperfusion continues: dobutamine, milrinone, dopamine	Check for fluid responsiveness; monitor for overload
Wet & Cold	- Inotropes to maintain perfusion - Vasopressors if needed - Once SBP > 90 mmHg, start diuretics - Escalate for refractory AHF	Avoid fluid bolus (risk of pulmonary edema) Avoid inotropes if LVOT obstruction

Key Points:

• IV fluids often worsen cardiogenic pulmonary edema → assess responsiveness before giving.

• Inotropes are essential for perfusion, but careful in LVOT obstruction or severe aortic stenosis.

• Early recognition & treatment of underlying cause (revascularization, valve repair) are critical.

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