What Causes Cardiogenic Shock?
Immediate Causes
Cardiogenic shock happens when the heart can't pump
enough blood to the body. This mostly occurs when the left ventricle isn't
working because the muscle isn't getting enough blood or oxygen due to an
ongoing
heart
attack. The weakened heart muscle can't pump enough oxygen-rich blood to
the rest of the body.
In about 3 percent of the cases of cardiogenic
shock, the right ventricle isn't working. This means the heart can't
effectively pump blood to the lungs, where the blood picks up oxygen to bring
back to the heart and the rest of the body.
When the heart isn't pumping enough blood to the
rest of the body, organs (such as the brain and kidneys) don't get enough
oxygen and can be damaged. Some of the things that might happen include the
following.
- Cardiogenic shock may result in death if the flow
of blood and oxygen to the organs isn't restored quickly. This is why emergency
medical treatment is essential.
- When organs don't get enough blood or oxygen and
stop working, cells in the organs die, and the organs may never go back to
working normally.
- As some organs stop working, they may cause
problems with other bodily functions. This, in turn, can make the shock worse.
For example:
- When the kidneys aren't working right, 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.
- When the liver isn't working right, the body
stops making proteins that cause the blood to clot. This can lead to more
bleeding if the shock is due to blood loss.
- How well the brain, kidneys, and other organs
recover depends on how long a person is in shock. The shorter the time in
shock, the less damage to the organs. This is another reason why it's so
important to get emergency treatment right away.
Underlying Causes
The underlying causes of cardiogenic shock are
conditions that weaken the heart and make it unable to pump enough blood and
oxygen to the body.
These conditions include:
- Heart attack.
Coronary
artery disease (CAD) usually causes heart attack. CAD is a condition in
which a material called plaque (plak) narrows or blocks the coronary arteries.
- Serious heart conditions that may cause a heart
attack and lead to cardiogenic shock, such as:
- Ventricular septal rupture. This is when the
wall between the two ventricles breaks down because cells in part of the wall
have died due to a heart attack. If the ventricles aren't separated, they can't
pump properly.
- Papillary muscle infarction or rupture. This
is when the muscles that help anchor the heart valves stop working or break
because their blood supply is cut off due to a heart attack. When this happens,
blood doesn't flow in the right way between the different chambers of the
heart, and they can't pump properly.
- Serious heart conditions that may happen with or
without a heart attack, including:
- Myocarditis, or inflammation of the heart
muscle.
- Endocarditis, or infection of the heart
valves.
- Arrhythmias,
or problems with the speed or rhythm of the heartbeat.
- Pericardial tamponade, or too much fluid or
blood around the heart. The fluid squeezes the heart muscle so it can't pump
properly.
- Pulmonary
embolism. This is a sudden blockage in a lung artery, usually due to a
blood clot that traveled to the lung from a vein in the leg.
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