Cardiogenic shock occurs if the heart suddenly can't pump enough oxygen-rich blood to the body. The most common cause of cardiogenic shock is damage to the heart muscle from a severe heart attack.
This damage prevents the heart’s main pumping chamber, the left ventricle (VEN-trih-kul), from working well. As a result, the heart can't pump enough oxygen-rich blood to the rest of the body.
In about 3 percent of cardiogenic shock cases, the heart’s lower right chamber, the right ventricle, doesn’t work well. This means the heart can't properly pump blood to the lungs, where it picks up oxygen to bring back to the heart and the rest of the body.
Without enough oxygen-rich blood reaching the body’s major organs, many problems can occur. For example:
- Cardiogenic shock can cause death if the flow of oxygen-rich blood to the organs isn't restored quickly. This is why emergency medical treatment is required.
- If organs don't get enough oxygen-rich blood, they won't work well. Cells in the organs die, and the organs may never work well again.
- As some organs stop working, they may cause problems with other bodily functions. This, in turn, can worsen shock. For example:
- If the kidneys aren't working well, the levels of important chemicals in the body change. This may cause the heart and other muscles to become even weaker, limiting blood flow even more.
- If the liver isn't working well, the body stops making proteins that help the blood clot. This can lead to more bleeding if the shock is due to blood loss.
How well the brain, kidneys, and other organs recover will depend on how long a person is in shock. The less time a person is in shock, the less damage will occur to the organs. This is another reason why emergency treatment is so important.
The underlying causes of cardiogenic shock are conditions that weaken the heart and prevent it from pumping enough oxygen-rich blood to the body.
Most heart attacks occur as a result of coronary heart disease (CHD). CHD is a condition in which a waxy substance called plaque (plak) narrows or blocks the coronary (heart) arteries.
Plaque reduces blood flow to your heart muscle. It also makes it more likely that blood clots will form in your arteries. Blood clots can partially or completely block blood flow.
Conditions Caused by Heart Attack
Heart attacks can cause some serious heart conditions that can lead to cardiogenic shock. One example is ventricular septal rupture. This condition occurs if the wall that separates the ventricles (the heart’s two lower chambers) breaks down.
The breakdown happens because cells in the wall have died due to a heart attack. Without the wall to separate them, the ventricles can’t pump properly.
Heart attacks also can cause papillary muscle infarction or rupture. This condition occurs if the muscles that help anchor the heart valves stop working or break because a heart attack cuts off their blood supply. If this happens, blood doesn't flow correctly between the heart’s chambers. This prevents the heart from pumping properly.
Other Heart Conditions
Serious heart conditions that may occur with or without a heart attack can cause cardiogenic shock. Examples include:
- Myocarditis (MI-o-kar-DI-tis). This is inflammation of the heart muscle.
- Endocarditis (EN-do-kar-DI-tis). This is an infection of the inner lining of the heart chambers and valves.
- Life-threatening arrhythmias (ah-RITH-me-ahs). These are problems with the rate or rhythm of the heartbeat.
- Pericardial tamponade (per-ih-KAR-de-al tam-po-NADE). This is too much fluid or blood around the heart. The fluid squeezes the heart muscle so it can't pump properly.
Pulmonary embolism (PE) is a sudden blockage in a lung artery. This condition usually is caused by a blood clot that travels to the lung from a vein in the leg. PE can damage your heart and other organs in your body.