The Human Circulatory System

What is Cardiogenic Shock?

Cardiogenic Shock

Cardiogenic shock, also known as cardiac shock, happens when your heart cannot pump enough blood and oxygen to the brain and other vital organs. This is a life-threatening emergency. It is treatable if diagnosed right away, so it’s important to know the warning signs.

Without oxygen-rich blood reaching the brain and other vital organs, your blood pressure drops, and your pulse slows. You may have symptoms such as confusion, sweating, and rapid breathing. You may also lose consciousness.

Most often the cause of cardiogenic shock is a serious heart attack. Other health problems that may lead to cardiogenic shock include heart failure, which happens when the heart can’t pump enough blood to meet the body’s needs; chest injuries; and blood clots in the lungs.

Treatment focuses on getting blood flowing properly and protecting organs from damage. Some people may need a heart transplant or a permanently implanted device to help keep blood flowing to the heart. If not treated quickly, cardiogenic shock can be fatal or lead to organ failure or brain injury.

What causes cardiogenic shock?

A heart attack is the most common cause of cardiogenic shock. Less often, another heart problem or a problem somewhere else in the body blocks blood flow coming into or out of the heart and leads to cardiogenic shock.

Heart attack and other heart problems: Cardiogenic shock usually develops very quickly when it follows a heart attack. Other heart conditions, such as heart failure or arrhythmia, can make it harder for the heart to deliver oxygen-rich blood to the organs, leading to cardiogenic shock.

Problems outside the heart: Cardiogenic shock can be caused by problems outside the heart, including fluid buildup in the chest, internal bleeding or blood loss, or pulmonary embolism, which occurs when a blood clot gets stuck in an artery of the lung. Trauma or injury to the chest can damage the heart so that it no longer pumps blood effectively.

Medicines or procedures: Rarely, some medicines can cause cardiogenic shock if you take a dose that is too high, or if your heart is not working well after a heart attack or other heart problem. Examples include heart medicines, such as beta blockers or calcium channel blockers, that treat high blood pressure. It is rare for medicines to cause cardiogenic shock, and you can lower your risk by taking the right doses at the right time.

Very rarely, a heart procedure, such as cardiac catheterization, may injure the heart itself or cause an abnormal heartbeat, called arrhythmia, that leads to cardiogenic shock.

Can cardiogenic shock be prevented?

The main cause of cardiogenic shock is a heart attack, which is a complication of coronary heart disease. You can lower your risk of cardiogenic shock by taking steps to prevent a heart attack or other heart problems. This means adopting heart-healthy lifestyle changes to help prevent or treat coronary heart disease.

Are you at risk for cardiogenic shock?

Certain factors may increase your risk for cardiogenic shock.

  • Age: People who are 75 or older have increased risk.
  • Race or ethnicity: Asian Americans and Pacific Islanders have a higher risk of cardiogenic shock than other racial or ethnic groups. Hispanics and African Americans are not typically at higher risk for cardiogenic shock, but they are less likely than whites to receive emergency lifesaving treatment to restore blood flow when they do have cardiogenic shock.
  • Sex: Cardiogenic shock may be more common in women than men. Women are also less likely than men to receive emergency treatment to restore blood flow when they have cardiogenic shock.
  • Heart and blood vessel problems, such as coronary heart disease, heart failure, and high blood pressure
  • Diabetes and prediabetes
  • Overweight and obesity
  • Past coronary artery bypass grafting (CABG)
  • Pneumothorax, a type of pleural disorder that can lead to a collapsed lung
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  • sepsis, a life-threatening inflammatory response to an infection

Symptoms

Symptoms of cardiogenic shock vary, depending on how quickly and how low your blood pressure drops. Cardiogenic shock may start with symptoms such as confusion or rapid breathing, or a person may have no symptoms and then suddenly lose consciousness. 

The most common signs of cardiogenic shock are:

  • Low blood pressure, which can make you feel dizzy, confused, and nauseous
  • Weak or irregular pulse

Symptoms of cardiogenic shock may include:

  • Breathing problems, including fast breathing and severe shortness of breath
  • Bulging veins in the neck
  • Clammy skin
  • Cold hands and feet
  • Fever
  • Loss of consciousness
  • Swelling of feet
  • Urinating much less than usual or not at all
  • Cardiac arrest

Many of these symptoms develop because the heart does not deliver enough blood to the body’s tissues and organs. For example, as blood pressure drops during cardiogenic shock, the body tries to compensate by limiting blood flow to the hands and feet, causing them to cool down.

As blood flow to the brain drops, the person may become confused or lose consciousness. The kidneys may shut down, producing less urine. Reduced blood flow in the lungs may lead to fluid buildup there, making it hard to breathe.

Diagnosis

Your doctor will ask you or your family members about your medical history, especially any symptoms of a heart attack before you became ill. Your doctor will also want to know about any medicines you are taking.

Physical exam

During a physical exam your doctor may:

  • Check your hands and feet for cold temperature or swelling.
  • Check your pulse. If your heart cannot pump strongly, your pulse may be weak and rapid. If cardiogenic shock was caused by doses of heart medicines that were too high, your pulse may be normal or slow.
  • Listen to your heart and lungs with a stethoscope for unusual sounds or heart rhythms.
  • Measure how much you urinate to check how well your kidneys are working.
  • Measure your blood pressure. Low blood pressure that does not return to normal on its own is a sign of cardiogenic shock.

Diagnostic tests and procedures

Your doctor may order one or more of the following tests and procedures to diagnose cardiogenic shock.

Chest X-ray: A chest X-ray is a fast and painless imaging test to look at the structures in and around your chest.

This test can help diagnose and check conditions such as pneumonia, heart failure, lung cancer, tuberculosis, sarcoidosis, and lung tissue scarring, called fibrosis. Doctors may use chest X-rays to see how well certain treatments are working and to check for complications after certain procedures or surgeries.

The test may be done in the doctor’s office, clinic, or hospital. You will stand, sit, or lie still for the test.

Chest X-rays have few risks. The amount of radiation used in a chest X-ray is very small. Talk to your provider if you are or could be pregnant.

Coronary angiography: Coronary angiography is a procedure that uses contrast dye, usually containing iodine, and X-ray pictures to detect blockages in the coronary arteries that are caused by plaque buildup. Blockages prevent your heart from getting oxygen and important nutrients.

This procedure is used to diagnose heart diseases or after abnormal results from tests such as an electrocardiogram (EKG) or an exercise stress test. If you are having a heart attack, coronary angiography can help your doctors plan your treatment.

Coronary angiography is often done in a hospital. You will stay awake, but you will get medicine to relax you during the procedure. Often, coronary angiography is done with a cardiac catheterization procedure. For this, your doctor will clean and numb an area on the arm, groin or upper thigh, or neck before making a small hole in a blood vessel. Your doctor will insert a catheter tube into your blood vessel. Your doctor will take X-ray pictures to help place the catheter in your coronary artery. After the catheter is in place, your doctor will inject the contrast dye through the catheter to highlight blockages and will take X-ray pictures of your heart. If blockages are detected, your doctor may use percutaneous coronary intervention, also known as coronary angioplasty, to improve blood flow to your heart.

After coronary angiography, your doctor will remove the catheter and close and bandage the opening on your arm, groin, or neck. You may develop a bruise and soreness where the catheter was inserted. You will stay in the hospital for a few hours or overnight. During this time, your healthcare team will check your heart rate and blood pressure.

Coronary angiography is a common procedure that rarely causes serious problems. However, as with any procedure involving the heart, there is some risk. These risks include bleeding, allergic reactions to the contrast dye, infection, blood vessel damage, arrhythmias, and blood clots that can trigger a heart attack or stroke. The risk of complications is higher in people who are older or who have chronic kidney disease or diabetes.

Echocardiography: Echocardiography, or echo, is a painless test that uses sound waves to create moving pictures of your heart. The pictures show the size and shape of your heart and how well your heart is pumping blood. A type of echo called Doppler ultrasound shows how well blood flows through your heart’s chambers and valves.

The illustration shows a patient having echocardiography. The patient lies on his left side. A sonographer moves the transducer on the patient’s chest, while viewing the echo pictures on a computer.

Echo can detect blood clots inside your heart, fluid buildup in the pericardium (the sac around the heart), tumors, and problems with the aorta. The aorta is the main artery that carries oxygen-rich blood from your heart to your body. Echo also can help your doctor find the cause of abnormal heart sounds, such as heart murmurs. Your doctor also might use echo to see how well your heart responds to certain heart treatments.

Electrocardiogram (EKG or ECG): An electrocardiogram, also called an ECG or EKG, is a simple, painless test that detects and records your heart’s electrical activity. An EKG can show how fast your heart is beating, whether the rhythm of your heartbeats is steady or irregular, and the strength and timing of the electrical impulses passing through each part of your heart. You may have an EKG as part of a routine exam to screen for heart disease.

An EKG may be recorded in a doctor’s office, an outpatient facility, in a hospital before major surgery, or as part of stress testing. For the test, you will lie still on a table. A nurse or technician will attach up to 12 electrodes to the skin on your chest, arms, and legs. Your skin may need to be shaved to help the electrodes stick. The electrodes are connected by wires to a machine that records your heart’s electrical activity on graph paper or on a computer. After the test, the electrodes will be removed.

An EKG has no serious risks. EKGs don’t give off electrical charges such as shocks. You may develop a slight rash where the electrodes were attached to your skin. This rash usually goes away on its own without treatment.

Other tests may give your doctor important information.

  • Blood gas tests that check the amounts of oxygen and carbon dioxide in the veins and arteries
  • Blood tests that check how well the heart, liver, and kidneys are working and look for increased lactate, or lactic acid, levels
  • Other heart imaging tests that look for heart disease or problems with how well the heart or its valves are working
Treatment

Cardiogenic shock is life-threatening, but it is treatable if diagnosed and treated quickly.

At the hospital, you may need medicines and a procedure to restore blood flow to your heart. You may also need other emergency treatment, including temporary medical devices, to stabilize or support you until you receive a permanent device or have a heart transplant.

People who have severe organ damage may not be expected to survive after cardiogenic shock. In that case, palliative care or hospice care may help them have a better quality of life with fewer symptoms in the short term.

Medicines: Medicine can help increase blood flow and protect against organ damage. Some medicines treat the underlying cause of cardiogenic shock, which is usually a heart attack.

  • Medicines to restore a regular heartbeat are called anti-arrhythmia medicines.
  • Blood thinners or antiplatelet medicines can dissolve blood clots and reduce platelets that may be blocking the coronary arteries.
  • Medicines that increase blood pressure and blood flow out of the heart are called vasopressors and inotropes, including norepinephrine and dobutamine.

Procedures: Some medical procedures may be done right away to restore blood flow within your heart and throughout your body, preventing organ damage.

Coronary artery bypass grafting (CABG): Coronary artery bypass grafting (CABG pronounced like “cabbage”), sometimes called coronary artery bypass surgery or just bypass surgery, is a procedure to improve poor blood flow to the heart muscle. The surgery creates new paths for blood to flow to the heart when the arteries that supply blood to the heart itself, called coronary arteries, are narrowed or blocked. The surgeon attaches a healthy piece of blood vessel from another part of the body on either side of a coronary artery blockage to bypass it. This surgery may lower the risk of serious complications for people who have obstructive coronary artery disease, which can cause chest pain or even heart failure. It may also be used in an emergency, such as a severe heart attack, to restore blood flow. 

Percutaneous cardiac intervention: Percutaneous coronary intervention (PCI), also called coronary angioplasty, is a nonsurgical procedure that improves blood flow to your heart. Doctors use PCI to open blood vessels supplying the heart that are narrowed or blocked by plaque buildup. PCI requires cardiac catheterization.

A cardiologist, the doctor who specializes in the heart, performs PCI in a hospital cardiac catheterization laboratory. Live X-rays help your doctor guide a catheter through your blood vessels into your heart, where special contrast dye is injected to highlight any blockage. To open a blocked artery, your doctor will insert another catheter over a guidewire and inflate a balloon at the tip of that catheter. Your doctor may also put a small mesh tube called a stent in your artery to help keep the artery open.

You may develop a bruise and soreness where the catheters were inserted. It also is common to have discomfort or bleeding where the catheters were inserted. You will recover in a special unit of the hospital for a few hours or overnight. You will get instructions on how much activity you can do and what medicines to take. You will need a ride home because of the medicines and anesthesia you received. Your doctor will check your progress during a follow-up visit. If a stent is implanted, you will have to take certain anticlotting medicines exactly as prescribed, usually for at least 3 to 12 months.

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Serious complications during a PCI procedure or as you are recovering after one are rare, but they can happen. This might include:

  • Bleeding
  • Blood vessel damage
  • Treatable allergic reaction to the contrast dye
  • Need for emergency coronary artery bypass grafting during the procedure
  • Arrhythmias, or irregular heartbeats
  • Damaged arteries
  • Kidney damage
  • Heart attack
  • Stroke
  • Blood clots

Sometimes chest pain can occur during PCI because the balloon briefly blocks blood supply to the heart. Restenosis, when tissue regrows where the artery was treated, may occur in the months after PCI. This may cause the artery to become narrow or blocked again. The risk of complications from this procedure is higher if you are older, have chronic kidney disease, are experiencing heart failure at the time of the procedure, or have extensive heart disease and more than one blockage in your coronary arteries.

Medical devices: You may need a medical device to aid, bring back, or maintain blood flow. This can help prevent organ damage from cardiogenic shock. Sometimes temporary devices are used to support people who are waiting for surgery to receive a permanent support device or a heart transplant.

  • An extracorporeal membrane oxygenation (ECMO) device temporarily replaces the function of the heart and lungs by circulating the blood and supplying oxygen to the body’s organs. It is connected to the patient through tubes placed in the large blood vessels near the base of the neck. The device draws blood from the right side of the heart and pumps it through a smaller device that works like an artificial lung to add oxygen. Then, the blood is returned to the left side of the heart so the oxygen-rich blood can be pumped throughout the body.
  • An intra-aortic balloon pump (IABP) may improve survival when used with ECMO device. An IABP may also be used for a short time in people who have cardiogenic shock from heart failure until another more permanent procedure can be done. An IABP helps the heart muscle pump as much blood as it can to the body, but the heart uses less energy to do it. The IABP is placed in the aorta, and a balloon at the tip of the device inflates and deflates to match the heart’s pumping rhythm.
  • Percutaneous circulatory assist devices (PCADs), including ventricular assist devices (VADs), can help support the heart until it recovers or while waiting for a heart transplant. A PCAD can help the heart work better if the patient is not eligible for a heart transplant. Risks include blood clots, bleeding, infection, device malfunction, and right-sided heart failure if a left-sided VAD was used.

Source: https://www.nhlbi.nih.gov/health/cardiogenic-shock

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