creation date: 2026-09-01 16:35
tags: Pathologies
Cardiogenic Shock
Background
Definitions
Shock is defined as a life-threatening condition of circulatory failure. It is a state of cellular tissue hypoxia due to inadequate oxygen delivery for the metabolic demands.
The effects of shock are initially reversible but can deteriorate to an irreversible state with multiorgan failure and death.
Four types of shock are recognized, of which multifactorial shock is possible. The specifics of each type are described in their respective pages:
- Distributive (66% – 62% septic shock, 4% other)
- Cardiogenic (16%)
- Hypovolemic (16%)
- Obstructive (2%)
The general approach to undifferentiated shock is described separately. This articles describes specific findings and treatment of this type of shock.
Etiology
Cardiogenic shock is characterized by intracardiac causes of cardiac pump failure. This results in decreased cardiac contractility and/or stroke volume and thus decreased cardiac output.
Failure to pump blood causes cellular hypoxia.
Cardiomyopathic
- Consist of failure of cardiac myocardium
- Most common cause is myocardial infarction (typically requires at least 40% of LV to be affected or any amount if there is significant ischemia or other conditions such as heart failure)
- Other causes include hypertrophic cardiomyopathy or diastolic heart failure but these rarely result in shock
Arrhythmic
- Both atrial and ventricular tachyarrhythmias and bradyarrhythmias can contribute to shock
- Can become shock is CO is compromised significantly such as with complete heart block
- CO can also become absent due to underlying rhythm (eg. pulseless VTach, Vfib)
Mechanical
- Mitral valve insufficiency or due to valvular defects from rupture of papillary muscle or chordae tendineae.
- Aortic insufficiency due to retrograde dissection into aortic valve ring or abscess of aortic ring
- Severe ventricular septal defects or rupture of intraventricular septum
Risk Factors
- Advanced age
- Asian and pacific Islanders
- Heart and blood vessel problems
- Diabetes
- Obesity
- Past history of coronary artery bypass grafting (CABG)
- Pneumothorax
- Sepsis
Clinical Presentation
Signs & Symptoms
Vitals:
- Tachycardia (may be normal on beta blocker or decreased with beta blocker overdose)
- Hypotension
- Tachypnea (unless severe shock)
- SpO2 usually normal (unless severe)
- Decreased pulse pressure
Presents with hypotension with manifestation of:
- Pulmonary edema
- Elevated CVP (>12 mmHg)
- Low SvO2 (<70%)
- Large, dilated ventricles and poor LV function
- Valvular or septal abnormalities on echocardiography
Specific findings also present based on etiology (eg. findings of MI)
History & Physical Exam
Diagnosis
Criteria
Shock is a clinical diagnosis.