Cardiogenic Shock
Inadequate tissue perfusion resulting from cardiac dysfunction
Clinical definition - decreased cardiac output and tissue hypoxia in the presence of adequate intravascular volume
Hemodynamic definition - sustained systolic BP <90 mm Hg, cardiac index<2.2 L/min/m2, PCWP >15 mm Hg

Causes of Cardiogenic Shock
Acute MI
Pump failure
Mechanical complications
Right ventricular infarction

Other conditions
End-stage cardiomyopathy
Myocarditis (fulminant myocarditis)
Myocardial contusion
Prolonged cardiopulmonary bypass
Septic shock with myocardial depression
Valvular disease

Initial Approach: Management
Assure oxygenation
Intubation and ventilation if needed
Venous access
Pain relief
Continuous EKG monitoring
Hemodynamic support
Fluid challenge if no pulmonary edema
Vasopressors for hypotension
- Dopamine
- Norepinephrine

Intra-aortic Balloon Counterpulsation
Reduces afterload and augments diastolic perfusion pressure
Beneficial effects occur without increase in oxygen demand
No improvement in blood flow distal to critical coronary stenosis
No improvement in survival when used alone
May be essential support mechanism to allow for definitive therapy

Pathophysiology of Cardiogenic Shock
Cardiogenic shock IS NOT simply the result of severe depression of LV function due to extensive myocardial ischemia/injury.

Depressed Myocardial Contractility combined with  Inadequate Systemic Vasoconstriction resulting from a systemic inflammatory response to extensive myocardial ischemia/injury results in cardiogenic shock .
The Overproduction of Nitric Oxide May Cause Both Myocardial Depression and Inappropriate Vasodilatation.
Thus, excess nitric oxide and peroxy nitrites may be a major contributor to cardiogenic shock complicating MI.

Acute Coronary Syndromes: Definitions
Acute coronary syndrome:
Constellation of clinical symptoms compatible with
acute myocardial ischemia
    ST-segment elevation MI (STEMI)
    Non-ST-segment elevation MI (NSTEMI)
    Unstable angina

Unstable angina:
    Angina at rest (usually >20 minutes)
    New-onset of class III or IV angina
    Increasing angina (from class I or II to III or IV)...

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