Cardiogenic Shock: Overview and More

Cardiogenic shock is a life-threatening condition in which the heart is not providing enough blood flow to the body. Symptoms of cardiogenic shock include extreme fatigue, shortness of breath, decreased urination, and confusion. This serious condition needs to be treated quickly for the best chance of survival.

This article discusses the causes, treatment, and prognosis of cardiogenic shock.

What Is Shock?

Shock is a state of very low blood pressure that affects the blood supply of the organs. Shock can happen because of infection (septic shock), allergic reaction (anaphylactic shock), brain injury (neurogenic shock), or bleeding (hypovolemic shock).

Cardiogenic shock is shock that is due to the heart's inability to provide blood flow.

The heart acts as a pump to supply nutrients and oxygen to the entire body. Cardiac output is the amount of blood flow pumped by the heart per minute. In cardiogenic shock, cardiac output is low, leading to low blood pressure and multiple organ failure.

Cardiogenic Shock Symptoms

Symptoms and signs of cardiogenic shock are related to low cardiac output and include:

• Extreme fatigue
• Light-headedness
• Confusion
• Loss of consciousness
• Low blood pressure
• Shortness of breath
• Decreased urination
• Paleness of the skin
• Cold extremities

What Causes Cardiogenic Shock?

Cardiogenic shock can have several causes:

• Heart attack (the most common cause, accounting for 80% of cases)
• Heart failure of any cause
• Cardiac tamponade (fluid buildup in the sac that surrounds the heart)
• Myocarditis (inflammation of the heart)
• Severe heart valve problems
• Arrhythmias (heart rhythm problems)
• Medication overdose, such as with beta-blockers or calcium channel blockers (medications to reduce blood pressure)

Diagnosing Cardiogenic Shock

Cardiogenic shock should be considered when blood pressure is low and not responding to intravenous (IV) fluids. Several tests can help differentiate cardiogenic shock from other types of shock.

Labs such as cardiac biomarkers, including, troponin (a protein found in heart muscles) and BNP (B-type natriuretic peptide, a hormone produced by your heart), can be elevated in cardiogenic shock. Other labs show signs of organ damage, such as acute kidney injury and liver injury.

Blood tests also typically show acidosis (a state in which body fluids are too acidic) and elevated levels of lactic acid (mainly produced in muscle cells and red blood cells).

Heart imaging, including transthoracic echocardiogram, is one of the most important diagnostic procedures in cardiogenic shock. An echocardiogram shows the heart's pumping function and valves, and rules out cardiac tamponade.

When necessary, the diagnosis of cardiogenic shock is confirmed with an invasive procedure called a right heart catheterization. In this procedure, a tube called a catheter is placed in a vein and into the right-sided chambers of the heart. This measures pressure and calculates cardiac output.

Treatment

Treating cardiogenic shock begins with correcting the underlying cause. Generally, treatment will require a level of care provided by an intensive care unit (ICU) or coronary care unit (CCU) and includes the following:

• A heart attack is treated with medication and placing stents in the blocked coronary artery.
• Tamponade is treated by removing the fluid in the sac around the heart, called a pericardiocentesis.
• Certain forms of myocarditis are treated with corticosteroids.
• Heart valve problems may require surgery.
  

Medications called inotropes (such as milrinone and dobutamine) can be used to help improve the heart's pumping function. Vasopressors like norepinephrine may be needed to raise the blood pressure.

Some people with cardiogenic shock require intubation (a breathing tube) for mechanical ventilation. This helps maintain oxygen levels and takes over the work of breathing.

Sometimes, special devices are required temporarily to help provide blood flow to the body. These are known as mechanical circulatory support devices, and are placed by cardiologists (specialists who treat conditions of the heart and blood vessels) or cardiothoracic surgeons (specialists who treat organs in the thoracic cavity, including the heart, lungs, and esophagus).

Examples of mechanical support devices include:

• Intra-aortic balloon pump
• Left ventricular assist devices (LVADs) like the Impella and TandemHeart
• Extracorporeal membrane oxygenation (ECMO)

When cardiogenic shock is not improving, permanent left ventricular support devices (LVADs) and heart transplant may be needed.

Prognosis

Cardiogenic shock is a very serious diagnosis with a poor prognosis. Unfortunately, survival rates are low.

However, newer team-based approaches and technology appear to be promising. One hospital that implemented a standardized team-based approach to treating cardiogenic shock saw prognosis improve for 3 in 4 people (75%) surviving beyond one month.

Hearing that your loved one has been diagnosed with cardiogenic shock can be overwhelming. In addition to worrying about your loved one, you may be faced with the stress of being in an ICU, communicating with healthcare providers, and making decisions on the patient's behalf.

Know that the medical team is working together to provide the best care possible. Staying rested to the best of your ability, making sure to eat and stay hydrated, taking a break outside, and seeking support from family and friends can help in this difficult time.

Summary

Cardiogenic shock is a serious, life-threatening condition in which the heart is not performing adequately. This causes organ failure and possibly death. Medication, medical procedures, and devices are used in the treatment of cardiogenic shock.