Epidemiology

Heart transplants remain relatively rare procedures worldwide. Around 3,700 heart transplants are performed each year in the United States, with approximately 5,000 conducted globally each year^[5][3]. More than half of all heart transplants worldwide take place in the United States. In 2020, just under 8,200 transplants were performed across the globe, with the United States performing 3,658 of them—the highest number of any country. Germany, France, and Spain had the next highest totals^[6].

The demand for heart transplants far exceeds the supply of available donor hearts. Currently, about 3,800 people in the United States are on the waiting list for a donor heart, and many will wait more than six months before receiving one^[5][15]. The number of people on waiting lists continues to grow, creating a significant gap between those who need transplants and the organs available. This shortage means that transplant teams must carefully select candidates who will benefit most from the procedure.

Heart transplants are possible for both children and adults. Most recipients are adults, though children and adolescents may also need them. In 2020, there were 465 pediatric heart transplants performed in the United States^[5]. Heart transplants are generally available for people up to age 70, and in some circumstances up to age 75^[6][12].

Causes

Heart transplants become necessary when a person’s heart is too damaged or weak to pump enough blood to meet the body’s needs. This condition is called end-stage heart failure, which means the heart has permanent damage that cannot be repaired with medications, stents, bypass procedures, or other treatments^[5]. End-stage heart failure is not a sudden event—it is a serious condition that develops and worsens over time.

In adults, several conditions can lead to the need for a heart transplant. Cardiomyopathy is one of the most common causes. This term refers to any disease that damages the heart muscle itself. The causes of cardiomyopathy can include infections and genetic diseases, though sometimes the cause remains unclear even after extensive testing^[6][1]. When the heart muscle weakens, it cannot contract properly to push blood through the body.

Coronary artery disease is another major cause. This condition involves blockages in the arteries that supply blood to the heart. These blockages can lead to heart attacks that cause irreversible damage to the heart muscle^[6][1]. Over time, repeated damage or severe blockages can destroy enough heart tissue that the organ can no longer function adequately.

Heart valve disease involves damage to the valves that control blood flow through the heart’s chambers. When valves do not open or close properly, the heart must work harder to pump blood, which can eventually lead to heart failure^[1][6]. Congenital heart defects—problems with the heart’s structure that a person is born with—can also lead to end-stage heart failure requiring a transplant^[6][1].

Dangerous recurring abnormal heart rhythms, called ventricular arrhythmias, that cannot be controlled by other treatments may also necessitate a heart transplant^[1]. In rare cases, a heart transplant is needed because a previously transplanted heart has failed^[1].

In children, heart failure most often results from either a congenital heart defect or cardiomyopathy^[1]. These conditions can severely limit a child’s ability to grow and develop normally, making a heart transplant necessary to save their life.

Risk Factors

Not everyone with heart failure is a suitable candidate for a heart transplant. Because donor hearts are in short supply, transplant teams must carefully evaluate each person to ensure they have the best chance of benefiting from the procedure long-term. People may not be eligible for a heart transplant if they have certain conditions that could complicate recovery or reduce the chances of success.

A current or recent history of cancer can disqualify someone from receiving a transplant, as can severe pulmonary hypertension (high blood pressure in the arteries of the lungs)^[5][15]. Severe disease affecting the brain’s blood vessels, advanced kidney, liver, or lung disease, and current infections such as HIV or hepatitis C are also reasons someone might not be eligible^[5][15].

Lifestyle factors can also affect eligibility. Use of tobacco, alcohol, or drugs within the previous six months typically disqualifies a person from receiving a transplant^[5][15]. A history of not taking medications as prescribed by doctors is also a concern, because after a transplant, patients must take medications every day for the rest of their lives^[5][15]. Obesity—having a body mass index (BMI) of 35 or higher—and poorly controlled diabetes can also make someone ineligible^[5][15].

However, people with advanced kidney, liver, or lung disease may still be candidates for multi-organ transplantation surgery, such as a heart-kidney, heart-liver, or heart-lung transplant^[1][5][15]. These combined procedures are performed at select medical centers that have the expertise to manage such complex surgeries.

Symptoms

People who need a heart transplant are living with severe heart failure, which produces symptoms that significantly limit their daily lives. Heart failure means the heart is unable to pump enough blood to meet the body’s needs, though it has not stopped working entirely. As the condition progresses, symptoms become more severe and harder to manage.

One of the most common and debilitating symptoms is shortness of breath. People with severe heart failure have difficulty breathing even during routine physical tasks like walking across a room or getting dressed. This shortness of breath can also occur when lying down, forcing people to sleep propped up on pillows or even sitting in a chair. The feeling of not being able to catch one’s breath can be frightening and exhausting.

Extreme fatigue is another major symptom. People with end-stage heart failure often feel too tired to do even simple activities. This fatigue is not the kind that improves with rest—it is a persistent exhaustion that comes from the heart’s inability to deliver enough oxygen-rich blood to the muscles and organs. People may find that they need to rest frequently throughout the day and that activities they once enjoyed are now impossible.

Chest pain can occur, especially in people whose heart failure is caused by coronary artery disease. The pain may feel like pressure, tightness, or aching in the chest. Some people also experience worsening chest pain as their condition deteriorates.

Swelling in the legs, ankles, and feet is common because the failing heart cannot pump blood efficiently, causing fluid to accumulate in the body’s tissues. People may notice their shoes no longer fit or that pressing on swollen areas leaves an indentation. This swelling can be uncomfortable and make walking difficult.

People with severe heart arrhythmias may experience palpitations—a sensation that the heart is racing, fluttering, or skipping beats. These irregular rhythms can be dangerous and may cause dizziness or fainting.

As heart failure worsens, other organs can be affected. The kidneys and liver may not function properly, leading to additional complications. Recurrent hospitalizations are common for people with progressive heart failure, as symptoms become harder to control even with medications and other treatments. Those who require multiple hospital admissions or who experience worsening kidney or liver function are at high risk for death within one year without a transplant^[7].

Prevention

Preventing the conditions that lead to end-stage heart failure is the most effective way to avoid the need for a heart transplant. Many of the diseases that damage the heart can be prevented or managed with healthy lifestyle choices and medical care.

Maintaining a heart-healthy diet is one of the most important preventive measures. This means eating plenty of fruits, vegetables, whole grains, and lean proteins while limiting saturated fats, trans fats, salt, and added sugars. A healthy diet helps prevent coronary artery disease, high blood pressure, and diabetes—all of which can lead to heart failure.

Regular physical activity strengthens the heart and improves circulation. Adults should aim for at least 150 minutes of moderate-intensity aerobic exercise each week. Even small amounts of activity, like walking, can make a significant difference in heart health.

Avoiding tobacco use is critical. Smoking damages blood vessels, raises blood pressure, and significantly increases the risk of heart disease. Quitting smoking at any age can improve heart health and reduce the risk of heart failure.

Limiting alcohol consumption is also important. Excessive drinking can weaken the heart muscle and lead to cardiomyopathy. Staying within recommended limits—no more than one drink per day for women and two for men—helps protect the heart.

Managing chronic conditions like high blood pressure, diabetes, and high cholesterol can prevent them from damaging the heart. Taking prescribed medications as directed, monitoring blood pressure and blood sugar levels, and working closely with healthcare providers are essential steps in preventing heart disease.

For people with existing heart conditions, following treatment plans carefully can slow the progression of disease and may prevent the need for a transplant. This includes taking medications correctly, attending regular check-ups, and reporting new or worsening symptoms promptly.

Genetic counseling and testing may be appropriate for people with a family history of cardiomyopathy or congenital heart defects. Early identification of genetic conditions allows for monitoring and interventions that can delay or prevent heart failure.

Pathophysiology

Understanding what happens in the body during heart failure and after a heart transplant helps explain why this surgery is necessary and what changes occur. In a healthy heart, the muscle contracts rhythmically to pump oxygen-rich blood throughout the body. The heart has four chambers—two upper chambers called atria and two lower chambers called ventricles. Blood flows through these chambers in a coordinated sequence, controlled by electrical signals and valves.

In heart failure, this coordinated pumping action becomes impaired. The heart muscle may become weak and unable to contract with enough force, or it may become stiff and unable to fill with blood properly. When the heart cannot pump efficiently, blood backs up in the lungs and other organs, causing fluid accumulation and swelling. At the same time, the body’s tissues do not receive enough oxygen and nutrients, leading to fatigue and organ dysfunction.

In cardiomyopathy, the heart muscle itself is diseased. The muscle fibers may become stretched and thinned, or thickened and rigid, depending on the type of cardiomyopathy. In either case, the heart’s ability to pump blood is severely compromised. When infections cause cardiomyopathy (a condition called myocarditis), inflammation damages the heart muscle cells, leaving scar tissue that cannot contract.

In coronary artery disease, the arteries that supply blood to the heart muscle become narrowed or blocked by fatty deposits called plaques. When the heart muscle does not receive enough oxygen-rich blood, areas of tissue die—this is a heart attack. After one or more heart attacks, large portions of the heart muscle may be replaced by scar tissue, which cannot pump blood. The remaining healthy muscle must work harder to compensate, but eventually it too fails.

During a heart transplant, surgeons perform what is called an orthotopic transplant, which is the most common technique. In this procedure, the patient’s diseased heart is removed and replaced with a healthy donor heart in the same position in the chest^[2][3]. A less common procedure, called a heterotopic transplant, leaves the recipient’s diseased heart in place and implants the donor heart alongside it to support circulation^[2][3].

The surgery requires the patient to be placed on a heart-lung machine, which temporarily takes over the function of the heart and lungs, maintaining blood circulation and delivering oxygen to the body while the surgeons work^[7]. The surgeons remove the damaged heart and connect the donor heart to the major blood vessels. Once blood flow is restored, the new heart begins to beat, often requiring support with medications initially^[7].

After the transplant, the recipient’s immune system recognizes the donor heart as foreign tissue and attempts to attack it—a process called rejection. To prevent this, transplant recipients must take immunosuppressive medications for the rest of their lives. These drugs suppress the immune system’s activity, allowing the body to accept the new heart^[5][11]. However, because the immune system is weakened, recipients become more vulnerable to infections and other complications.

The transplanted heart also differs from the original heart in one important way: it is denervated, meaning it no longer has direct nerve connections to the brain. In a normal heart, the nervous system helps regulate heart rate in response to activity and stress. A denervated heart relies on hormones in the bloodstream to adjust heart rate, which means it may respond more slowly to changes in physical activity. Over time, some nerve connections may regenerate, but the heart never fully regains normal nerve control.