Heart failure happens when your heart can’t pump as much blood as your body needs. Acute (sudden) heart failure is a medical emergency that can happen without warning.

Heart failure means your heart can’t pump enough blood to meet your body’s demands. This can be chronic, meaning it happens slowly over time. Or it can be acute, meaning it happens suddenly.

It’s estimated that 64 million people worldwide are living with heart failure. This condition is a major cause of people over age 65 being admitted to the hospital. This may be because people are living longer with heart disease, which can lead to heart failure over time.

Symptoms of acute heart failure can include:

Many of these symptoms can be related to water retention, which is when your body holds on to excess water. This can make you feel heavy or sluggish.

Acute heart failure can cause symptoms to come on suddenly. But your symptoms can also develop over time before you notice there’s a problem.

Other symptoms of heart failure include:

Heart failure is not the same thing as a heart attack. But, like a heart attack, acute heart failure can be a life threatening event. Someone with acute heart failure will typically need emergency hospital care. If your symptoms are sudden or severe, call 911 or your local emergency services for help.

If not treated, heart failure can lead to serious complications. These complications can include cardiac arrest, which is when your heart stops beating.

Some people with heart failure may have several health conditions. If that’s the case, it can be hard to know what’s causing your symptoms.

But when it comes to symptoms of heart failure, it’s best to get them checked by a doctor right away. According to a 2017 study, fast treatment of acute heart failure can lead to better outcomes.

The chambers where your blood is pumped out of the heart are called ventricles. These may stiffen so that they no longer fill properly. Or, if your heart muscle becomes weak, the ventricles can fail to pump hard enough.

Heart failure can begin on either the left or right side of your heart. Sometimes, both sides may fail at the same time. The different types of heart failure correspond to where the heart is failing:

Left-sided heart failure

This occurs when your left ventricle isn’t pumping efficiently. There are two types of left-sided heart failure:

  • Systolic heart failure happens when your left ventricle cannot squeeze (contract) strongly enough. This means it can no longer pump out blood to your body very well. It’s also called heart failure with reduced ejection fraction.
  • Diastolic heart failure happens when your left ventricle becomes stiff. If your ventricle is stiff, it cannot fill up with blood between heartbeats like it should. As a result, your body doesn’t get as much blood as it needs. This is also called heart failure with preserved ejection fraction.

Right-sided heart failure

This usually happens in people who also have left-sided heart failure. When your left ventricle has problems, the change in blood flow can eventually cause damage to the right side of your heart.

The right side of your heart moves blood from your veins to your lungs. If the right side of your heart is unable to pump effectively, too much blood can stay in your veins. This may cause swelling in places such as your legs or abdomen.

Other ways to classify heart failure

Sometimes, doctors also identify types of heart failure based on whether you have known (preexisting) heart disease. These types are:

Acute decompensated heart failure

Acute decompensated heart failure happens when you already have heart disease. This is the most common form of acute heart failure.

People with acute decompensated heart failure can sometimes have several conditions that affect their hearts, so it can be hard to know the exact cause of this type of heart failure.

De novo acute heart failure

De novo acute heart failure is less common. De novo is a medical term that means “for the first time.” This type describes heart failure when you do not have a previous diagnosis of heart disease.

The most common cause of de novo heart failure is lack of blood flow to your heart, which can be caused by conditions such as atherosclerosis.

Many conditions can weaken or damage the heart over time. This can lead to heart failure.

With chronic heart failure, your heart tries to adapt to the additional strain over time until it just can’t adapt anymore. That’s when acute heart failure happens.

It’s also possible for acute heart failure to happen even in people who otherwise seem healthy. There are a number of conditions that can put a sudden strain on your heart.

Causes of acute heart failure include:

These same conditions can also cause chronic heart failure.

In rare cases, acute heart failure can also be caused by conditions such as:

Risk factors for heart failure

Having one risk factor may be enough to trigger heart failure. And having a combination of risk factors typically means the chance of heart failure happening is higher.

Risk factors include:

In the United States, Black and Hispanic people receive heart failure diagnoses more often than people from other racial or ethnic groups. And Black people in the United States are also at the highest risk of dying from heart failure.

These trends are related to racism and inequities in healthcare, according to the American College of Cardiology.

To diagnose acute heart failure, your doctor will run certain tests. Your doctor can then identify your stage of heart failure, to help find the right treatment for you.

Tests for acute heart failure

Your doctor will assess your medical history and perform a physical exam. They’ll listen to your heart and lungs with a stethoscope to detect any congestion or abnormal heart rhythms. Your doctor may also check for fluid buildup in your abdomen, legs, and the veins in your neck.

In addition, your doctor might request tests such as:

  • Blood tests. These could include a BNP test, which measures a hormone related to heart failure.
  • Electrocardiogram (ECG or EKG). During this test, your doctor will attach electrodes to your skin and record your heart’s electrical activity.
  • Stress test. This test measures your heart activity during physical exercise. It’s not typically recommended if you already have signs and symptoms of heart failure.

Imaging tests that a doctor can use to help diagnose heart failure include:

  • Chest X-ray. This test allows your doctor to better examine your heart and lungs.
  • Echocardiogram. This test uses sound waves to form a live, moving image of your heart so your doctor can see which areas of your heart are affected.
  • Angiogram. If your doctor thinks you may have a blocked artery, they will insert a thin tube into your groin or arm and into your coronary arteries. After injecting dye through a catheter, your doctor can see an image of your arteries.

When needed, other imaging tests can be used to look for underlying causes of heart failure:

  • MRI scan. This test produces detailed images of your heart using magnets and radio waves.
  • CT scan. This test allows your doctor to see detailed images of your heart. It involves lying inside a machine while the images are taken using X-rays.

Together, your physical exam and test results can help your doctor learn about the health of your heart.

Classes and stages of heart failure

If you receive a heart failure diagnosis, your doctor may use a classification system to tell you what stage of heart failure you have. This can help guide your treatment.

The New York Heart Association classification is a symptom-based scale. It places heart failure in one of four categories:

  • Class 1. You don’t experience any symptoms at any time.
  • Class 2. You can perform daily activities with ease but feel fatigued or short of breath when you exert yourself.
  • Class 3. You have difficulty completing daily activities.
  • Class 4. You have heart failure symptoms like shortness of breath even when you’re at rest.

The American College of Cardiology/American Heart Association classification is a stage-based system. It’s used to identify your risk for or level of heart failure. The letters A to D convey the stage that you’re in:

  • Stage A: At risk of heart failure. You have one or more risk factors for heart failure, but you aren’t experiencing any symptoms.
  • Stage B: Pre-heart failure. Your test results show signs of heart disease, but you don’t have symptoms of heart failure.
  • Stage C: Symptomatic heart failure. You have heart disease, and you’re experiencing symptoms of heart failure.
  • Stage D: Advanced heart failure. You have advanced heart failure that affects your daily life and requires specialized treatments.

Doctors often use these two classification systems together to determine the best treatment or prevention plan for you.

There is no cure for heart failure, but treatment can help improve your quality of life. Acute heart failure can have lasting effects on your body. Because of this, treatment is centered on managing symptoms and preventing future heart failure.

If you experience acute heart failure, you’ll likely stay in the hospital until you’re in stable condition. During this time, you may need oxygen therapy. You might also need supplemental oxygen after you leave the hospital.

The cause of your acute heart failure will determine your treatment plan. In some cases, acute heart failure can be caused by undiagnosed chronic heart failure. Treatment for acute heart failure and chronic heart failure is often the same.

Treatment options for acute heart failure include medications, medical devices, and surgery.


In many cases, a combination of at least two medications is necessary to manage heart failure.

Some of these medications include:

  • Angiotensin converting enzyme (ACE) inhibitors. These medications help open your blood vessels, which lowers blood pressure and increases blood flow. This makes your heart’s job easier.
  • Angiotensin receptor blockers (ARBs). Much like ACE inhibitors, ARBs help to relax your blood vessels.
  • Beta-blockers. These medications reduce blood pressure and slow your heart rate. They help to normalize the rhythms of your heart.
  • Digoxin (Lanoxin). This drug strengthens the contractions of your heart and makes it beat more slowly.
  • Diuretics. Also known as water pills, these medications prevent fluid from accumulating in your body.
  • Aldosterone antagonists. These are another type of diuretic. They also reduce the amount of fluid in your body.

Depending on the cause of heart failure, a doctor may also prescribe medication to treat conditions such as:

Surgery and medical devices

Surgery is sometimes used to treat heart failure. Your doctor may use one of the following devices to help restore function:

  • Biventricular pacemaker. This device helps both sides of your heart beat at the correct speed by sending electrical impulses.
  • Implantable cardioverter defibrillators (ICDs). An ICD is implanted under your skin, like a pacemaker. It monitors your heart rate and uses an electrical signal to correct it when needed.
  • Heart pumps. An implant such as a ventricular assist device can help your heart pump blood more strongly.

Depending on your overall heart health, other procedures can include:

  • Heart valve replacement or repair. If your heart fails because of a problematic heart valve, your doctor may repair or replace the valve.
  • Coronary bypass surgery. In this surgery, your surgeon will remove a blood vessel from another part of your body. This blood vessel is fashioned into a new pathway to work around a clogged artery. Sometimes a less invasive alternative, such as angioplasty with stent placement, can be used instead.
  • Heart transplant. If your condition is severe and other treatments aren’t working, your doctor may recommend heart transplant surgery.

Tips for self-management

Focusing on certain behaviors can reduce your heart failure symptoms. This may also lessen your risk for future instances of heart failure.

If you smoke, talk with your doctor about making a plan to quit. Smoking has negative effects on heart hearth, including:

  • raising your blood pressure
  • making your heart race
  • lowering the amount of oxygen in your blood

Other changes to discuss with your doctor can include:

  • making changes to your diet, such as lowering your salt intake
  • managing your weight, if overweight or obesity is a concern
  • taking steps to reduce and manage stress

Be sure to follow your treatment plan carefully. This can help you manage your heart failure symptoms and any underlying conditions that may be affecting your heart.

Palliative and hospice care

Someone living with a serious condition like heart failure can access palliative care at any stage of their condition. Palliative care is intended to support overall wellness and quality of life and can happen alongside other treatments.

With very severe heart failure, people may choose to access hospice care to receive supportive care at the end of life.

Some risk factors, such as aging, can’t be avoided. The key to preventing heart failure is to reduce the risk factors that you can control.

Many of the lifestyle measures recommended for heart failure recovery can also reduce or eliminate conditions that lead to heart failure. These conditions include high blood pressure and high cholesterol.

If you’re at risk for heart failure, you should consider these measures to promote heart health:

  • maintain a healthy weight, if overweight or obesity is a concern
  • get regular physical activity
  • eat a balanced diet that’s low in red meat and sugar
  • quit smoking, if you smoke
  • find ways to manage stress
  • get enough sleep
  • limit your alcohol consumption, if you drink
  • manage any other health conditions you may have

If you’re making big changes to your diet or activity levels, be sure to check in with your doctor first.

It’s also important to get regular medical checkups and report any unusual symptoms to your doctor. The faster that you identify your symptoms and get started with treatment, the better your outlook.

Your outlook depends on your overall health, as well as the cause and degree of your heart failure. Hospital treatment is generally the first step to recovery. Many people are able to manage their symptoms over time with heart medications or implanted medical devices.

After an acute heart failure diagnosis, it’s important to follow your treatment plan carefully. Be on the lookout for symptoms of heart failure and call your doctor if your condition changes. If you think you could be having an episode of acute heart failure, get emergency help.

Although there’s no cure for heart failure, treatment can relieve your symptoms and reduce your risk for future incidents.