Cardiogenic shock

Definition

Cardiogenic shock is a condition in which your heart suddenly can't pump enough blood to meet your body's needs. Cardiogenic shock is most often caused by a severe heart attack.

Cardiogenic shock is rare, but it's often fatal if not treated immediately. If treated immediately, about half the people who develop cardiogenic shock survive.

Symptoms

Cardiogenic symptoms include:

• Rapid breathing
• Severe shortness of breath
• Sudden, rapid heartbeat (tachycardia)
• Confusion
• Loss of consciousness or fainting
• Weak pulse
• Sweating
• Pale skin
• Cold hands or feet
• Urinating less than normal or not at all

Symptoms of a heart attack
Because cardiogenic shock usually occurs in people who are having a severe heart attack, it's important to know the signs and symptoms of a heart attack. These include:

• Pressure, fullness or a squeezing pain in the center of your chest that lasts for more than a few minutes
• Pain extending beyond your chest to your shoulder, arm, back, or even to your teeth and jaw
• Increasing episodes of chest pain
• Prolonged pain in the upper abdomen
• Shortness of breath
• Sweating
• Impending sense of doom
• Fainting
• Nausea and vomiting

If you seek medical attention quickly when having these signs or symptoms, you can decrease the chance that you'll develop cardiogenic shock.

When to see a doctor
Getting heart attack treatment quickly improves your chance of survival and minimizes damage to your heart. Don't "tough out" these symptoms for more than five minutes. Call 911 or other emergency medical services for help. If you don't have access to emergency medical services, have someone drive you to the nearest hospital.

Causes

Cardiogenic shock happens when your heart can't pump enough blood to the rest of your body. Most commonly, cardiogenic shock happens when your heart's main pumping chamber, the left ventricle, is damaged due to a lack of oxygen caused by a heart attack.

A heart attack occurs when one or more of the arteries supplying your heart with oxygen-rich blood (coronary arteries) become blocked. Over time, a coronary artery can become narrowed from the buildup of cholesterol. This buildup — collectively known as plaques — in arteries throughout the body is called atherosclerosis.

During a heart attack, one of these plaques can rupture and a blood clot forms on the site of the rupture and blocks the flow of blood through the artery. Without oxygen-rich blood circulating to that area of your heart, the heart muscle can weaken and progress into cardiogenic shock.

Rarely, cardiogenic shock happens when your heart's right ventricle is damaged. Your heart's right ventricle sends blood to your lungs to receive oxygen before being pumped to the rest of your body. Damage to the right ventricle makes it so your heart can't effectively pump blood to your lungs, so your body doesn't get sufficient oxygen.

Although heart attacks are the most common cause, cardiogenic shock can also occur due to other conditions, such as inflammation of the heart muscle (myocarditis) or infection of the heart valves (endocarditis). Other causes include drug overdoses or poisoning with substances that can affect your heart's pumping ability.

Risk factors

Some people who have a heart attack have a greater risk of developing cardiogenic shock than others have. Factors that increase your risk of cardiogenic shock include:

• Being age 65 or older
• Having a history of heart failure or previous heart attack
• Having blockages (coronary artery disease) in several of your heart's main arteries

Complications

If not treated immediately, cardiogenic shock can be fatal. Another serious complication of cardiogenic shock is organ damage.

If your heart can't pump enough oxygenated blood out to the rest of your body, your liver, kidneys or other organs could be damaged. The damage to your liver or kidneys can worsen cardiogenic shock, since the kidneys release chemicals that keep your muscles functioning and the liver releases proteins that help your blood to clot. Depending on how long you're in cardiogenic shock, the damage could be permanent.

Tests and diagnosis

Cardiogenic shock is usually diagnosed in an emergency setting. Doctors will check for signs and symptoms of shock, and will then perform additional tests to find out what's causing your condition.

Tests to diagnose cardiogenic shock include:

• Blood pressure measurement. People in shock often have very low blood pressure readings. If the person in shock is brought to the hospital by ambulance, blood pressure will be measured before he or she arrives at the hospital.
• Electrocardiogram (ECG). This is the first test done to diagnose a heart attack. It's often done while you're being asked questions about your symptoms. This test records the electrical activity of your heart via electrodes attached to your skin. Impulses are recorded as "waves" displayed on a monitor or printed on paper. Because injured heart muscle doesn't conduct electrical impulses normally, the ECG may show that a heart attack has occurred or is in progress.
• Chest X-ray. An X-ray image of your chest allows your doctor to check the size and shape of your heart and its blood vessels.
• Blood tests. Blood will be drawn to see if your kidneys or liver might be damaged, to look for signs of an infection in your heart, and to see if you've had a heart attack. Another type of blood test (arterial blood gas) may also be used to determine how much oxygen is present in the blood.
• Echocardiogram. This test uses sound waves to produce an image of your heart. During an echocardiogram, sound waves are directed at your heart from a wand-like device (transducer) held on your chest. The sound waves bounce off your heart and are reflected back through your chest wall and processed electronically to provide video images of your heart. An echocardiogram can help identify whether an area of your heart has been damaged by a heart attack and isn't pumping normally.
• Coronary catheterization (angiogram). This test can show if your coronary arteries are narrowed or blocked. A liquid dye is injected into the arteries of your heart through a long, thin tube (catheter) that's pushed through an artery, usually in your leg, to the arteries in your heart. As the dye fills your arteries, the arteries become visible on X-ray, revealing areas of blockage.
  
  Additionally, while the catheter is in position, your doctor may treat the blockage by performing an angioplasty. Angioplasty uses tiny balloons threaded through a blood vessel and into a coronary artery to widen the blocked area. In most cases, a mesh tube (stent) is also placed inside the artery to hold it open more widely and prevent re-narrowing in the future.
  

Treatments and drugs

Cardiogenic shock treatment focuses on repairing the damage to your heart muscle and other organs caused by lack of oxygen.

Emergency life support
Emergency life support is a necessary treatment for most people who have cardiogenic shock. During emergency life support, you're given extra oxygen to breathe to minimize damage to your muscles and organs. If necessary, you'll be connected to a breathing machine (ventilator). You'll receive medications and fluid through an intravenous (IV) line in your arm.

Medications
Medications to treat cardiogenic shock work to improve blood flow through your heart and increase your heart's pumping ability.

• Aspirin. You may be given aspirin by emergency medical personnel soon after they arrive on the scene or as soon as you get to the hospital. Aspirin reduces blood clotting and helps keep your blood flowing through a narrowed artery. Take an aspirin yourself while waiting for help to arrive only if your doctor has previously told you to do so if symptoms of a heart attack occur.
• Thrombolytics. These drugs, also called clot busters, help dissolve a blood clot that's blocking blood flow to your heart. The earlier you receive a thrombolytic drug after a heart attack, the greater the chance you'll survive and lessen the damage to your heart. You'll usually receive thrombolytics only if emergency cardiac catheterization isn't available.
• Superaspirins. Doctors in the emergency room may give you other drugs that are similar to aspirin to help prevent new clots from forming. These include medications, such as clopidogrel (Plavix) and others called platelet glycoprotein IIb/IIIa receptor blockers.
• Other blood-thinning medications. You'll likely be given other medications, such as heparin, to make your blood less likely to form more dangerous clots. Heparin is given intravenously or by an injection under your skin and is usually used during the first few days after a heart attack.
• Inotropic agents. You may be given medications, such as dopamine or epinephrine, to improve and support your heart function until other treatments start to work.

Medical procedures
Medical procedures to treat cardiogenic shock usually focus on restoring blood flow through your heart. They include:

• Angioplasty and stenting. Usually, once blood flow is restored through a blocked artery, the signs and symptoms of cardiogenic shock improve. Emergency angioplasty opens blocked coronary arteries, letting blood flow more freely to your heart. Doctors insert a long, thin tube (catheter) that's passed through an artery, usually in your leg, to a blocked artery in your heart. This catheter is equipped with a special balloon. Once in position, the balloon is briefly inflated to open up a blocked coronary artery. At the same time, a metal mesh stent may be inserted into the artery to keep it open long term, restoring blood flow to the heart. In most cases, you doctor will place a stent coated with a slow-releasing medication to help keep your artery open.
• Balloon pump. Depending on your condition, your doctors may choose to insert a balloon pump in the main artery of your heart (aorta). The balloon pump inflates and deflates to mimic the pumping action of your heart, helping blood flow through.

Surgery
If medications and medical procedures don't work to treat cardiogenic shock, your doctor may recommend surgery.

• Coronary artery bypass surgery. Bypass surgery involves sewing veins or arteries in place at a site beyond a blocked or narrowed coronary artery. This restores blood flow to the heart. Your doctor may suggest that you have this procedure after your heart has had time to recover from your heart attack.
• Surgery to repair an injury to your heart. Sometimes an injury in your heart, such as a tear in one of your heart's chambers or a damaged heart valve, can cause cardiogenic shock. If an injury causes your cardiogenic shock, your doctor may recommend surgery to correct the problem.
• Heart pumps. These mechanical devices, called ventricular assist devices (VADs), are implanted into the abdomen and attached to a weakened heart to help it pump. Implanted heart pumps can extend and improve the lives of some people with end-stage heart failure who aren't eligible for or able to undergo heart transplantation or are waiting for a new heart.
• Heart transplant. If your heart is so damaged that no other treatments work, a heart transplant may be a last resort for treating cardiogenic shock.

Prevention

The best way to prevent cardiogenic shock is to prevent a heart attack from happening. The same lifestyle changes you can use to treat heart disease can help prevent a heart attack. These lifestyle changes include:

• Control high blood pressure (hypertension). One of the most important things you can do to reduce your heart attack and cardiogenic shock risk is to keep your blood pressure under control. Exercising, managing stress, maintaining a healthy weight, and limiting sodium and alcohol intake are all ways to keep hypertension in check. In addition to recommendations for lifestyle changes, your doctor may prescribe medications to treat hypertension, such as diuretics, angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers.
• Don't smoke. Quitting smoking reduces your risk of having a heart attack. Several years after quitting, a former smoker's risk of stroke is the same as that of a nonsmoker.
• Maintain a healthy weight. Being overweight contributes to other risk factors for heart attack and cardiogenic shock, such as high blood pressure, cardiovascular disease and diabetes. Weight loss of as little as 10 pounds (4.5 kilograms) may lower your blood pressure and improve your cholesterol levels.
• Lower the cholesterol and saturated fat in your diet. Eating less cholesterol and fat, especially saturated fat, may reduce your risk of developing heart disease. If you can't control your cholesterol through dietary changes alone, your doctor may prescribe a cholesterol-lowering medication.
• Exercise regularly. Exercise reduces your risk of having a heart attack in many ways. Exercise can lower your blood pressure, increase your level of high-density lipoprotein (HDL) cholesterol, and improve the overall health of your blood vessels and heart. It also helps you lose weight, control diabetes and reduce stress. Gradually work up to 30 minutes of activity — such as walking, jogging, swimming or bicycling — on most, if not all, days of the week.

If you have a heart attack, quick action can help prevent cardiogenic shock from occurring. Seek emergency medical help immediately if you think you're having a heart attack.