Cardiogenic shock

Definition

Cardiogenic shock is a state in which the heart has been damaged so much that it is unable to supply enough blood to the organs of the body.

Alternative Names

Shock - cardiogenic

Causes, incidence, and risk factors

Shock occurs whenever the heart is unable to pump as much blood as the body needs.

The most common causes are serious heart complications. Many of these occur during or after a heart attack (myocardial infarction). These complications include:

• Dangerous heart rhythms, such as ventricular tachycardia, ventricular fibrillation, or supraventricular tachycardia
• Very slow heart rhythm (bradycardia) or heart conduction block
• Tear or rupture of the wall (septum) between the left and right ventricle
• Tear or rupture of the muscles or tendons that support the heart valves, especially the mitral valve
• A large section of heart muscle that no longer moves well or does not move at all
• Rupture of the heart muscle due to damage from the heart attack

Symptoms

• Profuse sweating, moist skin
• Rapid breathing
• Rapid pulse
• Restlessness, agitation, confusion
• Skin that feels cool to the touch
• Pale skin color or blotchy (mottled) skin
• Weak (thready) pulse
• Decreased mental status
  • Loss of ability to concentrate
  • Loss of alertness
• Coma

Signs and tests

An examination will reveal:

• Low blood pressure (less than 90 systolic)
• Blood pressure may drop more than 10 points when you stand up after lying down (orthostatic hypotension)
• Weak (thready) pulse

To diagnose cardiogenic shock, a catheter (tube) may be placed in the pulmonary artery (right heart catheterization). Measurements often indicate that blood is backing up into the lungs and the heart is not pumping properly.

Tests include:

• Coronary angiography
• Echocardiogram
• Electrocardiogram
• Nuclear scans

Other tests may be recommended to determine why the heart is not functioning properly.

Laboratory tests include:

• Arterial blood gas
• Blood chemistry (chem-7, chem-20, electrolytes, cardiac enzymes)
• CBC

Treatment

Cardiogenic shock is a medical emergency. Treatment requires hospitalization. The goal of treatment is to save your life and treat the cause of shock.

Medications may be needed to increase blood pressure and heart function, including:

• Dopamine
• Dobutamine
• Epinephrine
• Norepinephrine

When an arrhythmia is serious, urgent treatment may be needed to restore a normal heart rhythm. This may include:

• Electrical "shock" therapy (defibrillation or cardioversion)
• Implanting a temporary pacemaker
• Medications given through a vein (intravenous)

You may receive pain medicine if necessary. Bed rest is recommended to reduce demands on the heart.

Getting oxygen lowers the workload of the heart by reducing tissue demands for blood flow.

You may receive intravenous fluids, including blood and blood products, if needed.

Other treatments for shock may include:

• Cardiac catheterization with coronary angioplasty and stenting
• Heart monitoring, including hemodynamic monitoring, to guide treatment
• Heart surgery (coronary artery bypass surgery, heart valve replacement, left ventricular assist device)
• Intra-aortic balloon counterpulsation (IABP) to improve heart and blood vessel function
• Pacemaker

Expectations (prognosis)

In the past, the death rate from cardiogenic shock ranged 80 - 90%. In more recent studies, this rate has improved to between 50 - 75%.

When cardiogenic shock is not treated, the outlook is not good.

Complications

• Brain damage
• Kidney damage
• Liver damage

Calling your health care provider

Go to the emergency room or call the local emergency number (such as 911) if you have symptoms. Cardiogenic shock is a medical emergency.

Prevention

You may reduce the risk by quickly and aggressively treating any related disorders.

References

Anderson JL, Adams CD, Antman EM, Bridges CR, Califf RM, Casey DE, et al. ACC/AHA 2007 guidelines for the management of patients with unstable angina/non-ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines for the Management of Patients With Unstable Angina/Non-ST-Elevation Myocardial Infarction) developed in collaboration with the American College of Emergency Physicians, the Society for Cardiovascular Angiography and Interventions, and the Society of Thoracic Surgeons endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation and the Society for Academic Emergency Medicine. J Am Coll Cardiol. 2007;50:e1-e57.

Antman EM. ST-elevation myocardial infarction: management. In: Libby P, Bonow RO, Mann DL, Zipes DP. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Philadelphia, Pa: Saunders; 2007:chap 51.