Cardiogenic Shock Lecture Notes

Introduction

• Presenter: Eddie Watson
• Lecture: Fourth in series on shock, focusing on cardiogenic shock.
• Previous Topics: Hypovolemic shock, general understanding of shock.
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Cardiogenic Shock Overview

• Definition: Shock state originating from a heart issue.
• Main Problem: Heart (pump) failure—heart can’t pump enough blood to meet body’s needs.

Causes of Cardiogenic Shock

1. Filling Issues (Diastolic Heart Failure):

   • Enlarged, stiff ventricle walls
   • Decreased space and compliance
   • Leads to decreased preload and cardiac output.

2. Contraction Issues:

   • Cardiomyopathies & Heart Failure: Heart weakens over time.
   • Myocardial Infarction (MI): Ischemia or muscle cell death reduces contractility.

3. Arrhythmias:

   • Conduction issues through SA node, AV node, etc.
   • Includes bradycardia, tachycardia, conduction blocks.
   • Impacts preload, heart rate, and contractility.

4. Structural Issues (Valvular Diseases):

   • Valvular regurgitation
   • Causes backflow, reducing forward blood ejection and cardiac output.

Pathophysiology

• Heart not pumping forward leads to blood backing up:
  • Left atrium → pulmonary arteries → lungs → right side of heart → body.

Signs and Symptoms

• Angina (Chest Pain): Main symptom.
• Blood Pressure: Decreased (hypotension)
• Heart Rate: Increased (tachycardia)
• Skin: Cool, clammy due to peripheral vasoconstriction.
• Backup Indicators: Cardiomegaly, pulmonary edema, jugular venous distension (JVD), peripheral edema.

Diagnostic Tests

• Lab Tests:
  • Serum Lactate
  • Arterial Blood Gas
  • Troponins (heart damage indicator)
• Imaging and Monitoring:
  • Chest X-ray (pulmonary congestion)
  • EKG (arrhythmias, MI)
  • Echocardiogram (gold standard)
  • Hemodynamic values (CVP, pulmonary capillary wedge pressure, cardiac output/index).

Treatment Modalities

1. Oxygen Supply: Ensure adequate oxygen delivery.
2. Cardiovascular Support:
   • Increase systemic vascular resistance with vasopressors (e.g., levo, neo, epinephrine).
   • Inotropes for contraction (e.g., dobutamine, primacor).
   • Antiarrhythmics and pacing for arrhythmias (e.g., amiodarone, lidocaine).
   • Temporary assist devices (e.g., intra-aortic balloon pump, VA ECMO).
3. Repairing the Heart:
   • PCI or open-heart surgery for MI.
   • Valve repair/replacement for structural issues.
   • Long-term assist devices or heart transplant for unrepairable conditions.

Conclusion

• Main Takeaway: Cardiogenic shock is due to the heart’s inability to pump blood.
• Learned Topics: Causes, signs, diagnostics, treatments.
• Next Lesson: Obstructive shock.
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