It can also be caused by a sudden decompressurization (e.g. in an aircraft), where air bubbles are released into the bloodstream (Henrys law), causing heart failure. Diagnosis
Electrocardiogram
An electrocardiogram helps to establish the exact diagnosis and guides treatment, it may reveal:

Abnormal heart rhythms, such as bradycardia (slowed heart rate)
myocardial infarction (ST-elevation MI, STEMI, is usually more dangerous than non-STEMIs; MIs that affect the ventricles are usually more dangerous than those that affect the atria; those affecting the left side of the heart, especially the left ventricle, are usually more dangerous than those affecting the right side, unless that side is severely compromised)
Signs of cardiomyopathy

Echocardiography
Echocardiography may show poor ventricular function, signs of PED, rupture of the interventricular septum, an obstructed outflow tract or cardiomyopathy. Swan-Ganz catheter
The Swan–Ganz catheter or pulmonary artery catheter may assist in the diagnosis by providing information on the hemodynamics. Biopsy
When cardiomyopathy is suspected as the cause of cardiogenic shock, a biopsy of heart muscle may be needed to make a definite diagnosis. Cardiac index
If the cardiac index falls acutely below 2.2 L/min/m2, the person may be in cardiogenic shock. Treatment
Depending on the type of cardiogenic shock, treatment involves infusion of fluids, or in shock refractory to fluids, inotropic medications. In case of an abnormal heart rhythm immediate synchronized cardioversion or anti-arrhythmic agents may be administered, e.g. adenosine.Positive inotropic agents (such as dobutamine or milrinone), which enhance the hearts pumping capabilities, are used to improve the contractility and correct the low blood pressure.
Care is directed to the dysfunctional organs (dialysis for the kidneys, mechanical ventilation for lungs dysfunction).Mortality rates have been decreasing in the United States. This is likely due to the rapid identification and treatment of the CS. Some studies have suggested that this possibly related to the increased use of coronary reperfusion strategies, like heart stents. Nonetheless, the mortality rates remain high. Multi-organ failure is associated with higher rates of mortality. Signs and symptoms
The presentation is the following:
Anxiety, restlessness, altered mental state due to decreased blood flow to the brain and subsequent hypoxia. Low blood pressure due to decrease in cardiac output. A rapid, weak, thready pulse due to decreased circulation combined with tachycardia. Cool, clammy, and mottled skin (cutis marmorata) due to vasoconstriction and subsequent hypoperfusion of the skin. Distended jugular veins due to increased jugular venous pressure. Oliguria (low urine output) due to inadequate blood flow to the kidneys if the condition persists. Rapid and deeper respirations (hyperventilation) due to sympathetic nervous system stimulation and acidosis. Fatigue due to hyperventilation and hypoxia. Absent pulse in fast and abnormal heart rhythms. Pulmonary edema, involving fluid back-up in the lungs due to insufficient pumping of the heart. Causes
Cardiogenic shock is caused by the failure of the heart to pump effectively. It is due to damage to the heart muscle, most often from a heart attack or myocardial contusion. Other causes include abnormal heart rhythms, cardiomyopathy, heart valve problems, ventricular outflow obstruction (i.e. systolic anterior motion (SAM) in hypertrophic cardiomyopathy), or ventriculoseptal defects.