Acyanotic heart disease is a type of congenital heart defect that causes abnormal blood flow. It can range from mild to severe. Babies with the condition can seem out of breath and fatigued.

Congenital heart disease refers to birth defects that affect the heart. They’re the most common type of birth defects, affecting nearly 1% of births — or 40,000 infants — per year in the United States.

Congenital heart disease is divided into two broad categories: cyanotic and acyanotic. The most common form is acyanotic, which includes conditions like ventricular septal defect (VSD) and atrial septal defect (ASD).

Read on to learn more about the different forms of acyanotic heart disease, how it’s diagnosed, and how it’s treated.

There are two categories of congenital heart defects: cyanotic and acyanotic.

Acyanotic is more common, making up about 75% of cases. Cyanotic heart disease affects about 25% of babies with congenital heart disease.


Acyanotic heart disease involves heart defects that cause abnormal blood flow, but oxygen levels in the blood remain typical. Babies born with this condition do not have any immediate symptoms, but health problems can develop over time.

Abnormal blood flow can cause increased blood pressure, putting strain on the heart. This can weaken the heart, increasing the chance of heart failure.

Another potential complication is abnormally high blood pressure in the lungs, which is called pulmonary hypertension. It can cause symptoms such as:

  • breathlessness
  • dizziness
  • fainting
  • fatigue


Cyanotic heart disease refers to heart defects that cause abnormal blood flow and low oxygen levels in the blood.

The lack of oxygen in the blood may cause areas of the skin to have a bluish-colored tint. Babies born with this condition may have bluish fingers, toes, lips, or skin.

Other symptoms may include:

  • breathlessness
  • chest pain
  • fainting
  • fatigue
  • palpitations

There are several different types of acyanotic heart defects that can affect the heart walls, valves, or blood vessels. The most common types include:

Ventricular septal defect

Ventricular septal defect (VSD) is a hole or opening in the wall that separates the two lower chambers of the heart. These chambers are called ventricles.

Atrial septal defect

Atrial septal defect (ASD) is a hole or opening in the wall that separates the two upper chambers of the heart. These chambers are called atria.

Pulmonary valve stenosis

The pulmonary valve is one of four valves that help manage blood flow in the heart. It allows blood to flow from the right ventricle to the artery that delivers blood to the lungs.

Pulmonary valve stenosis occurs when the pulmonary valve becomes narrowed. This means the right ventricle has to work harder to pump blood.

Aortic valve stenosis

The aortic valve allows blood to flow from the left ventricle to the aorta, which is the main artery that moves blood from the heart to the body.

Aortic valve stenosis makes the aortic valve narrower. This makes the left ventricle work harder to move blood to the body.

Patent ductus ateriosus

A patent ductus ateriosus (PDA) is a hole in the aorta that hasn’t closed. This may cause extra blood to pump from the aorta into the lung arteries.

The heart and lungs may need to work harder, leading to congestion in the lungs.

Symptoms of acyanotic heart disease depend on the type and severity of the defect. In some cases, people born with acyanotic heart disease may not have symptoms until later in life, during childhood or adulthood.

While mild defects may cause no symptoms, more severe defects can cause symptoms such as:

  • fast heartbeat
  • shortness of breath
  • trouble feeding
  • sleepiness

Experts don’t know exactly why congenital heart defects happen, but they’re likely due to a combination of genetic and environmental factors.

Potential contributing factors include:

  • family genetic history
  • exposure to harmful chemicals or air pollution during pregnancy
  • the birthing parent’s diet
  • conditions during pregnancy, such as diabetes, obesity, or high blood pressure
  • infections during pregnancy
  • medication use during pregnancy
  • smoking during pregnancy

Many congenital heart defects are now diagnosed during pregnancy using a type of ultrasound called fetal echocardiogram. This creates images of the developing baby’s heart.

However, some congenital heart defects are diagnosed after birth, later in childhood, or into adulthood.

Treatment depends on the type and severity of the heart defect. Some infants and children may need surgery to repair the heart or blood vessels, but others may only need nonsurgical procedures.

One option is a procedure called cardiac catheterization. During this procedure, a doctor inserts a long tube, called a catheter, through the blood vessels into the heart. They can use this to take measurements, perform tests, and repair any issues.

Some heart defects can’t be fully repaired, but treatment may still improve blood flow and heart function. Many people with congenital heart defects need specialized long-term care.

About 80% of children with congenital heart disease live into adulthood.

The outlook for infants and children born with congenital heart disease depends on:

  • the severity of the defect
  • when the diagnosis is made
  • the treatment for the defect

According to the National Center on Birth Defects and Developmental Disabilities, about 1 in 4 babies with congenital heart disease have a critical congenital heart defect. An estimated 69% of babies with critical defects live to at least 18 years of age.

By comparison, about 95% of babies born with a non-critical congenital heart defect live to 18 years.

Acyanotic heart disease is a type of congenital heart defect that affects blood flow and can range from mild to severe.

While doctors can repair some defects with surgery or other procedures, others can’t be fully repaired. However, there are a range of treatment options that mean many babies born with congenital heart defects can live long, healthy lives.