Definition and Overview

Cardiogenic shock is a life-threatening medical condition that occurs when the heart is severely damaged that it loses its ability to pump enough blood to the rest of the body. Decreased cardiac output results in reduced supply of oxygen and nutrients to the vital organs, including the brain, heart, and lungs. Unless normal blood flow to the body is immediately restored, cells and tissue will begin to die, and multiple organs will stop functioning.

Although very rare, cardiogenic shock remains to be the most common cause of death in acute myocardial infarction patients. Without access to aggressive medical care, mortality rates can be as high as 80-90%. The key to improving treatment outcomes is to promptly restore the heart’s ability to contract with medications and certain medical procedures.

Cardiogenic shock has high morbidity, mortality, and disability rates. Of those 10-20% patients who survive the condition, many fail to regain functional capacity and are permanently disabled.

Causes of Condition

Cardiogenic shock occurs when the heart’s left (most common) or right ventricle (rare) is damaged or has weakened, compromising the heart’s pumping capacity. Damage to the left ventricle can weaken the heart muscle and cause heart failure. Damage to the right ventricle, on the other hand, prevents the heart from pumping blood to the lungs.

Cardiogenic shock can also be caused by:

  • Myocarditis, or inflammation of the heart muscle

  • Dangerous arrhythmias, such as ventricular tachycardia, ventricular fibrillation, and supraventricular tachycardia

  • Pericardial tamponade - A condition characterised by the presence of excessive amount of blood or fluid around the heart that prevents the heart muscle from pumping properly.

  • Pulmonary embolism - Refers to the sudden blockage of a lung artery by blood clots.

  • Endocarditis, or infection of the heart valves

  • Tear or rupture of tendons or muscles that support the heart valves or the wall between the lower heart chambers

Factors that can increase a person’s risk of cardiogenic shock are:

  • Coronary heart disease (CHD)

  • Diabetes

  • High blood pressure

  • History of heart attack or heart failure

  • Old age

Cardiogenic shock can be avoided by lowering one’s risk of a heart attack, which can be achieved by:

  • Exercising regularly

  • Making lifestyle changes, such as stopping smoking and eating a healthy diet that is low in saturated fat and cholesterol

  • Keeping high blood pressure and diabetes under control

  • Maintaining a healthy weight

  • Managing physical and emotional stress

Key Symptoms

The symptoms of cardiogenic shock begin to show when vital organs, including the brain, lungs, liver, and kidneys malfunction because they do not have enough supply of oxygen and nutrients. These symptoms include:

  • A weak pulse

  • Abnormal heart rhythms

  • Altered mental state

  • Anxiety

  • Chest pain

  • Coma

  • Decreased or zero urine output

  • Fatigue

  • Hyperventilation

  • Inability to concentrate or lack of alertness

  • Lightheadedness

  • Low blood pressure

  • Pale skin

  • Pulmonary oedema

  • Rapid breathing and heartbeat

  • Sweating

People suffering from cardiogenic shock also commonly show symptoms of a heart attack, including:

  • Squeezing pain in the chest that commonly radiates to the jaw, back, shoulder, and arm

  • Increasing episodes of chest pain

  • Prolonged pain in the upper abdomen

  • Feeling unusually tired for no reason, often a few days before the heart attack

  • Nausea and vomiting

Who to See and Types of Treatments Available

Cardiogenic shock is a life-threatening medical condition that requires immediate medical care. Normally, emergency medical workers connect the patient to a ventilator and provide them with aspirin as soon as they arrive at the scene or as soon as the patient reaches a hospital’s emergency department. The primary goals of emergency treatment are to increase the body’s oxygen level and remove blood clots that may be blocking the flow of blood to arteries. Other drugs, such as thrombolytics, superaspirins, inotropic agents, and other blood-thinning medications are also often provided.

Cardiogenic shock is diagnosed using the following tests and procedures:

  • Electrocardiogram (ECG) - This test is used to detect abnormalities in the heart’s electrical activity and signs of heart damage caused by coronary heart disease.

  • Coronary angiography - A test that uses special x-rays to detect blockage in the coronary arteries.

  • Blood tests - When the heart muscle dies due to a severe heart attack, certain proteins are released into the bloodstream. Such proteins can be detected and measured with blood tests.

  • Chest x-ray - Used to determine if the condition is caused by pericardial tamponade and if there are any structural changes to the heart and its blood vessels.

Treatment

  • Medications - Patients are often promptly provided with medications to reduce the risk of blood clotting (aspirin and superaspirins), dissolve existing blood clots (thrombolytics), and improve the heart function (inotropic agents).

  • Angioplasty and stenting - This is a minimally invasive procedure that aims to widen blocked arteries using a catheter with a balloon at its tip. For the procedure, a thin and flexible tube (catheter) is threaded through a small incision or puncture in the groin or arm to the blocked artery. The balloon is then inflated and deflated several times until the blockage has cleared. If the artery is damaged beyond repair, coronary artery bypass surgery is performed. It involves using blood vessels from other areas of the body to bypass the narrowed heart artery.

  • Surgical repair - If the condition is due to a tear in the tendons or muscles that support the heart or in the wall between the lower heart chambers, traditional open surgery can be performed to make necessary repairs.

  • Heart transplant - A severely damaged heart can be removed and replaced with a healthy heart, usually from a person who has suffered irreversible brain injury or is brain dead. However, there are not enough hearts available for everyone who is undergoing the procedure. Thus, candidates go through a selection process that determines the urgency of their condition and their risk of dying unless they receive a new heart immediately. When all challenges are considered, a heart transplant can improve a cardiogenic shock patient’s chances of cure. The average one-year survival rate for heart transplant patients is 85%.

References:

  • Hollenberg S. Cardiogenic shock. In: Goldman L, Schafer AI, eds. Goldman’s Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 107.

  • Gheorghiade M, Filippatos GS, Felker GM. Diagnosis and management of acute failure syndromes. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, Pa: Saunders; 2011:chap 27.

  • What is a cardiogenic shock? National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/dci/Diseases/shock/shock_what.html.

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