Heart failure

Heart failure, also known as congestive heart failure, is when the heart does not work as well as it should in pumping blood and oxygen around the body. This can damage the organs and cause extra fluid to build up in the body. It occurs when the heart muscle becomes too weak to effectively pump blood around the body.

Heart failure is a long-term condition that worsens over time. It is more common in elderly people, and it can be life-threatening. The survival rate for people with heart failure depends on how severe their case is, however proper treatment can improve the signs and symptoms of heart failure and may help some people live longer.

Heart failure usually develops slowly and gets progressively worse (chronic heart failure), although it can occur suddenly. It often develops after other conditions have weakened or damaged the heart, such as the following.

• Coronary heart disease: This is the most common cause of heart failure. In this disease, atherosclerotic plaque builds up in the arteries, reducing blood supply to the heart.
• Heart attack: This occurs when blood supply to the heart is completely cut off. A heart attack can damage the heart muscle to the extent that the heart can no longer pump normally.
• High blood pressure (hypertension): The heart has to work harder than normal to pump blood around the body in high blood pressure. Over time, this can make the heart muscle too stiff or too weak to properly pump blood.
• Inflammation of the heart muscle (myocarditis): This is most commonly caused by a virus, including the COVID-19 virus. It can lead to left-sided heart failure.
• Congenital heart defects: If a person is born with problems with their heart’s structure, such as chambers or valves that have not formed correctly, the rest of the heart has to work harder to pump blood. This can lead to heart failure.
• Irregular heartbeat: Having an abnormal heart rhythm such as atrial fibrillation may cause the heart to work extra hard.
• Infections and other diseases: These can contribute to the slow development of heart failure.

Sudden (acute) heart failure may be caused by the following.

• An allergic reaction
• A whole-body illness
• Blood clots in the lungs
• Viruses that attack the heart muscle
• Severe infections
• Certain medications

Pathophysiology of heart failure

Heart failure typically begins with the left side of the heart, in particular the left ventricle – the heart’s main pumping chamber. The right side of the heart can also be involved, or both sides.

How well the heart is pumping can be measured by how much blood is pumped out with each beat (ejection fraction). A healthy heart will have an ejection fraction of 50 per cent or higher – it pumps out at least half the volume of blood that fills its chambers with each beat. The ejection fraction result is used to help determine the severity of heart failure and to guide treatment.

In heart failure, the left ventricle may not fill between beats or may have become stiff and unable to squeeze effectively. The heart muscle may become damaged and weak, and eventually, the ventricles may stretch so much that the heart cannot pump enough blood through the body.

There are many types of heart failure. Some can be categorised by the side of the heart in which they occur.

Left-sided heart failure

This type of heart failure affects the left side of the heart. Examples include diastolic heart failure and systolic heart failure. In this type of heart failure, fluid may back up in the lungs, causing symptoms such as shortness of breath.

Diastolic heart failure (heart failure with preserved ejection fraction)

In diastolic heart failure, also known as heart failure with preserved ejection fraction (HFpEF) or "stiff" heart failure, the left ventricle of the heart muscle becomes too stiff and cannot relax properly or stretch effectively to relieve pressure in the heart as it pumps, which causes fluid build-up.

HFpEF has become the most common type of heart failure globally, but despite this, there are currently no treatment options for it. To address this critical unmet need, HRI has launched an international research project investigating new therapeutic strategies for HFpEF.

Systolic heart failure (heart failure with reduced ejection fraction)

In systolic heart failure, also known as heart failure with reduced ejection fraction, the heart muscle becomes weak and fails to pump blood effectively, which causes fluid to build up and pool around the lungs and other parts of the body.

Right-sided heart failure

This type of heart failure affects the right side of the heart and is most commonly caused by heart failure in the left side of the heart. It can also be caused by particular problems with the lungs and in other organs. In this type of heart failure, fluid may back up in the abdomen, legs and feet, causing symptoms such as swelling in those areas.

Heart failure is a condition that usually develops slowly and gets progressively worse. There are four stages of heart failure.

Stage A heart failure

This is considered pre-heart failure. A person with Stage A heart failure is at high risk of developing heart failure because they have a family history of the disease or have one or more of the medical conditions that are a risk for heart failure, such as coronary heart disease, diabetes and high blood pressure.

Stage B heart failure

This is considered pre-heart failure. A person in Stage B heart failure has been diagnosed with a dysfunction in their heart but has never had symptoms of heart failure.

Stage C heart failure

A person with Stage C heart failure has been diagnosed with heart failure and has experienced signs and symptoms of the condition.

Stage D heart failure

A person with Stage D heart failure – the final stage of heart failure – has advanced symptoms of the condition that do not improve with treatment.

Difficulty breathing or shortness of breath is a key symptom of heart failure. A person suffering this symptom may:

• find physical activity difficult
• wake up in the night due to difficulty breathing
• find it uncomfortable to lie flat, as this can affect the ability to breathe normally.

Other signs and symptoms of heart failure can include:

• fatigue and weakness
• a rapid or irregular heartbeat
• swelling in the legs, ankles, feet or stomach bloating
• coughing or wheezing
• sudden weight gain due to fluid retention
• lack of appetite and nausea
• difficulty concentrating
• chest pain.

Heart failure signs and symptoms can range from mild to severe, and they may come and go. As heart failure worsens over time, more or different signs or symptoms may present themselves.

It’s important to seek emergency treatment if any of the following symptoms are experienced. These signs may be due to heart failure, but can also indicate other serious heart and lung conditions:

• chest pain
• fainting or severe weakness
• sudden shortness of breath with coughed-up mucus
• a rapid or irregular heartbeat accompanied by chest pain, shortness of breath or fainting.

Heart failure water retention and swollen feet

In heart failure, the heart does not work as well as it should in pumping blood and oxygen around the body, which can cause the body to retain water and cause symptoms such as swollen feet, ankles and legs. These symptoms will vary depending on the type of heart failure.

In right-sided heart failure, fluid may back up in the abdomen, legs and feet, causing symptoms such as swollen feet.

In left-sided heart failure, fluid may back up in the lungs, causing symptoms such as shortness of breath.

To diagnose heart failure, your doctor will assess your symptoms, take your medical and family history, and perform a physical examination that may contain some of the following tests. These tests can confirm a diagnosis of heart failure and identify the type.

• Echocardiogram: This takes an ultrasound of the heart to examine its shape and function.
• Electrocardiogram: This measures the electrical activity generated by the heart as it contracts.
• Exercise stress test: This test usually involves walking on a treadmill while connected to a heart monitor, to monitor how the heart works and responds during physical activity, when it is working at its hardest.
• Angiogram: This procedure checks whether the arteries to the heart are narrowed or blocked.
• Chest x-rays, lung function and blood tests

More than 900,000 people in the UK are living with heart failure, and heart failure affects over 26 million people worldwide.¹ It places a significant burden on patients and the healthcare system.

Between 50 to 75 per cent of people diagnosed with heart failure die within five years of diagnosis.²

One way to prevent heart failure is to lead a healthy lifestyle to prevent and manage the risk factors that can cause it.

• Eat a healthy, nutritious diet: Eat a diet that is low in salt, saturated fat, trans fat, LDL cholesterol and sugar, and full of plenty of vegetables, fruit and whole grains.
• Exercise regularly: Being physically active can help keep the body and heart healthy and strong.
• Reduce alcohol: Avoid or limit alcohol intake, as drinking too much alcohol can weaken the heart muscle.
• Quit smoking: Quitting smoking can reduce the risk the developing heart disease and heart failure.
• Maintain a healthy weight: People at an unhealthy weight have a higher risk of developing heart failure, as well as other risk factors, such as high cholesterol. Small lifestyle changes like exercising regularly can help you reach and maintain a healthy weight.
• Manage high blood pressure: The heart works harder than normal to pump blood around the body if blood pressure is high. Decreasing salt intake and other dietary changes can help manage high blood pressure.
• Manage diabetes: This can increase the risk of high blood pressure and coronary heart disease. Leading a healthy lifestyle as well as making some dietary changes can help manage diabetes.

These healthy lifestyle changes can also to help manage and prevent other conditions that can increase the risk of heart failure, such as coronary heart disease and heart attack.

There is no cure for heart failure and it cannot be reversed, making the research HRI has conducted investigating new therapeutic strategies for HFpEF critical for improving the health outcomes of people with heart failure.

While there is no cure, there is a range of strategies to manage and treat heart failure.

• Lifestyle changes: Maintaining a healthy lifestyle that includes limiting salt intake and managing fluid balance under the guidance of your doctor is very important in managing heart failure.
• Medications: You may be prescribed medicines to treat different aspects of heart failure, such as medicines to lower blood pressure and reduce strain on the heart, medicines to help the heart pump slower and stronger, and medicines to help reduce fluid build-up that leads to swelling in the body.
• Surgery or medical devices: In some cases, these may be needed to help maintain regular heart function. These can include a pacemaker to electrically stimulate the heart to keep it to a regular rhythm, bypass surgery to improve blood flow to the heart, heart valve repairs or replacements, or a heart transplant in severe cases.

HRI is conducting innovative research to develop new therapies for detecting and managing heart failure and other cardiovascular diseases.

Our Cardiometabolic Disease Research Group is investigating “stiff” heart failure (HFpEF). By understanding which factors contribute to the development of HFpEF, identifying the exact mechanisms leading to it and highlighting who is most at risk, we can build the foundations for novel drug development for effective treatment. Successfully developing a drug to improve or reverse HFpEF could save millions of lives worldwide.