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
Right ventricular infarction
Myocarditis (fulminant myocarditis)
Prolonged cardiopulmonary bypass
Septic shock with myocardial depression
Initial Approach: Management
Intubation and ventilation if needed
Continuous EKG monitoring
Fluid challenge if no pulmonary edema
Vasopressors for hypotension
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)
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)...