7 Key Signs and Symptoms of Patent Ductus Arteriosus (PDA)

Patent ductus arteriosus (PDA) is a congenital heart defect that occurs when the ductus arteriosus—a blood vessel that connects the pulmonary artery to the aorta during fetal development—fails to close after birth. In healthy newborns, this vessel typically closes within the first few days of life. However, when it remains open, it can cause abnormal blood flow between the heart and lungs, leading to various symptoms and potential complications.

The severity of symptoms associated with PDA depends largely on the size of the opening and the amount of blood flowing through it. While small PDAs may produce no noticeable symptoms, moderate to large PDAs can significantly impact heart and lung function. Understanding the signs and symptoms of this condition is crucial for early detection and appropriate medical intervention.

1. Heart Murmur

One of the most characteristic and often earliest detected signs of patent ductus arteriosus is a continuous heart murmur, frequently described as a “machinery murmur” due to its distinctive sound. This murmur occurs because blood flows continuously through the open ductus arteriosus from the aorta (which carries oxygenated blood at high pressure) back into the pulmonary artery (which normally carries blood at lower pressure to the lungs).

Healthcare providers typically detect this murmur during routine physical examinations using a stethoscope. The murmur is usually most audible in the upper left chest area, just below the collarbone. The continuous nature of this sound—present during both systole (heart contraction) and diastole (heart relaxation)—distinguishes it from many other types of heart murmurs.

In premature infants, the murmur may be less pronounced or even absent initially, making diagnosis more challenging. The intensity of the murmur often correlates with the size of the PDA, though this is not always a reliable indicator of severity.

2. Rapid or Difficult Breathing

Respiratory difficulties are among the most concerning symptoms of patent ductus arteriosus, particularly in infants. When the ductus arteriosus remains open, excess blood flows to the lungs, causing them to become congested with fluid. This pulmonary overcirculation makes breathing more laborious and less efficient.

Parents and caregivers may notice several breathing-related signs:

• Tachypnea (abnormally rapid breathing rate)
• Shortness of breath, especially during feeding or crying
• Grunting sounds while breathing
• Flaring of the nostrils with each breath
• Retractions (visible pulling in of the chest wall between or under the ribs during inhalation)

Infants with significant PDAs may breathe 60 times per minute or more when the normal rate is 30-60 breaths per minute. This increased respiratory effort can be exhausting for babies and may interfere with feeding and normal development.

3. Poor Feeding and Growth Difficulties

Feeding problems are particularly common in infants with moderate to large patent ductus arteriosus. The combination of increased work of breathing and the heart’s extra workload makes feeding an exhausting activity for affected babies. These infants may tire quickly during feedings, take longer to finish bottles or breastfeed, or consume less than normal amounts.

The consequences of poor feeding extend beyond immediate nutrition concerns:

• Inadequate weight gain or failure to thrive
• Slow growth compared to developmental milestones
• Falling off their expected growth curve on pediatric growth charts
• Appearing smaller than other infants of the same age
• Increased irritability due to hunger despite frequent feeding attempts

Additionally, the body’s increased metabolic demands due to the heart working harder means that even when infants do consume adequate calories, their bodies may burn through these resources faster than normal, further contributing to growth difficulties.

4. Excessive Sweating

Profuse sweating, particularly during feeding or physical activity, is a telltale sign of patent ductus arteriosus in infants and young children. This symptom occurs because the heart must work significantly harder than normal to pump blood throughout the body while also dealing with the abnormal recirculation of blood through the open ductus arteriosus.

The excessive sweating associated with PDA typically manifests as:

• Beads of sweat on the forehead, scalp, or back of the neck
• Damp clothing or bedding, even in cool environments
• Particularly noticeable perspiration during feeding sessions
• Cold, clammy skin despite sweating

This compensatory response reflects the cardiovascular system’s strain as it attempts to meet the body’s oxygen demands despite the inefficient circulation pattern created by the PDA. Parents often describe their babies as working hard during activities that should be relatively effortless for healthy infants.

5. Rapid or Pounding Heart Rate

Tachycardia, or an abnormally fast heart rate, frequently accompanies patent ductus arteriosus. The heart beats faster in an attempt to compensate for the inefficient circulation caused by blood being shunted back to the lungs instead of going to the rest of the body. This increased heart rate represents the cardiovascular system’s effort to maintain adequate blood flow and oxygen delivery to tissues.

Manifestations of elevated heart rate in PDA include:

• Resting heart rate consistently above normal range for age
• Visible pulsations in the chest wall or neck
• Bounding or vigorous peripheral pulses (particularly noticeable in the wrists, feet, or temples)
• Wide pulse pressure (significant difference between systolic and diastolic blood pressure readings)

In severe cases, parents might notice their child’s heartbeat simply by observing the chest or feeling the pulse. The heart’s increased workload over time can lead to cardiac remodeling and enlargement if the PDA remains untreated.

6. Frequent Respiratory Infections

Children with patent ductus arteriosus are significantly more susceptible to respiratory infections, including pneumonia, bronchiolitis, and other lung infections. The increased blood flow to the lungs creates an environment where fluid accumulates more easily, and the lungs’ natural defense mechanisms may be compromised.

These recurrent infections present several challenges:

• More frequent episodes of colds, coughs, and respiratory illnesses compared to peers
• Infections that last longer or are more severe than typical childhood illnesses
• Greater likelihood of requiring hospitalization for respiratory problems
• Persistent congestion or wheezing
• Difficulty recovering fully between illness episodes

The congested lungs associated with PDA provide an ideal environment for bacterial and viral pathogens to proliferate. Additionally, the extra work required for breathing may compromise the effectiveness of coughing and other mechanisms that normally help clear infections from the respiratory system.

7. Fatigue and Exercise Intolerance

As children with patent ductus arteriosus grow older, fatigue and reduced exercise tolerance become increasingly apparent symptoms. While infants may show this as excessive sleeping or lethargy, older children typically demonstrate decreased stamina during physical activities compared to their peers.

This symptom manifests in various ways depending on age:

• Infants: excessive sleepiness, weak cry, general listlessness
• Toddlers: preference for sedentary activities, frequently asking to be carried
• School-age children: inability to keep up with peers during play or sports, needing frequent rest breaks
• Adolescents: avoiding physical education or sports participation, shortness of breath with mild exertion

The underlying cause is insufficient oxygen delivery to muscles and organs during physical activity. Because some blood that should be going to the body is being recirculated to the lungs through the PDA, the amount available for working muscles is reduced. Over time, children may self-limit their activity levels, potentially leading to reduced physical fitness and social isolation from peers.

Main Causes of Patent Ductus Arteriosus

The exact cause of patent ductus arteriosus is not fully understood, but researchers have identified several factors that increase the risk of this congenital heart defect:

Premature Birth: This is the most significant risk factor for PDA. The ductus arteriosus is programmed to close shortly after birth in response to increased oxygen levels and changes in prostaglandin levels. Premature infants, especially those born before 28 weeks of gestation, may not have fully developed the mechanisms needed to close this vessel properly. The earlier the birth, the higher the risk of PDA.

Genetic Factors: PDA can run in families, suggesting a genetic component. Certain genetic syndromes and chromosomal abnormalities are associated with increased PDA risk, including Down syndrome, congenital rubella syndrome, and various other genetic conditions affecting heart development.

Maternal Factors During Pregnancy: Several maternal conditions and exposures increase the risk of PDA in offspring:

• Rubella (German measles) infection during the first trimester of pregnancy
• Maternal diabetes, particularly if poorly controlled
• Substance use during pregnancy, including alcohol consumption
• Use of certain medications that affect fetal development
• High altitude residence during pregnancy (possibly due to lower oxygen levels)

Gender: PDA occurs approximately twice as often in females as in males, though the reason for this difference is not completely understood.

Other Congenital Heart Defects: PDA often occurs alongside other structural heart problems. When multiple heart defects are present, the ductus arteriosus may remain open as part of a broader pattern of abnormal cardiac development.

Family History: Having a first-degree relative (parent or sibling) with PDA or other congenital heart defects increases an individual’s risk, supporting the role of hereditary factors in this condition.

Frequently Asked Questions

Can patent ductus arteriosus close on its own?

In some cases, particularly in premature infants, a small PDA may close spontaneously during the first few months of life. However, the likelihood of spontaneous closure decreases significantly after the first few weeks. Full-term infants with PDA rarely experience spontaneous closure after the first few days of life. The size of the PDA is also a factor—smaller openings have a better chance of closing naturally than larger ones.

Is patent ductus arteriosus a serious condition?

The seriousness of PDA depends on its size and the amount of abnormal blood flow it creates. Small PDAs may cause no symptoms and require only monitoring. However, moderate to large PDAs can lead to serious complications if left untreated, including heart failure, pulmonary hypertension (high blood pressure in the lungs), and increased risk of endocarditis (heart infection). Early detection and appropriate management are important to prevent these complications.

How is patent ductus arteriosus diagnosed?

PDA is typically diagnosed through several methods. The first clue is often a heart murmur detected during a physical examination. To confirm the diagnosis, doctors may order an echocardiogram (ultrasound of the heart), which can visualize the open ductus arteriosus and assess its size and the direction of blood flow. Other diagnostic tools may include chest X-rays, electrocardiograms (ECG), and cardiac catheterization in certain cases.

Are babies with PDA born with symptoms?

Not necessarily. Many babies with PDA appear normal at birth, particularly if the opening is small. Symptoms typically develop over the first few days to weeks of life as the pressure in the pulmonary arteries decreases (which normally happens after birth), allowing more blood to flow through the PDA from the aorta to the pulmonary artery. Premature infants may show symptoms sooner, sometimes within the first days of life.

Can adults have patent ductus arteriosus?

Yes, although PDA is typically diagnosed in infancy or childhood, some people reach adulthood with an undiagnosed PDA, particularly if it is small and causes minimal symptoms. Adults with undetected PDA may experience gradual onset of symptoms such as shortness of breath, fatigue, or palpitations. Some may develop complications like pulmonary hypertension or atrial fibrillation. Adults who are diagnosed with PDA should be evaluated by a cardiologist to determine if intervention is necessary.

What is the difference between PDA in premature versus full-term babies?

PDA is much more common in premature infants due to developmental immaturity of the mechanisms that normally close the ductus arteriosus after birth. In premature babies, the PDA may be more likely to close spontaneously with time or medical management, and the approach to management may be more conservative initially. In full-term infants, PDA is usually due to a structural abnormality, is less likely to close on its own, and may require earlier intervention. The symptoms may also be more pronounced in full-term infants with PDA compared to premature infants with similar-sized defects.

Does patent ductus arteriosus affect life expectancy?

With appropriate diagnosis and management, most people with PDA can live normal, healthy lives with normal life expectancy. However, if a significant PDA remains untreated, it can lead to serious complications over time that may affect quality of life and longevity. These complications include irreversible pulmonary hypertension (Eisenmenger syndrome), heart failure, and increased risk of endocarditis. This is why early detection and appropriate intervention when indicated are so important.

References:

• Mayo Clinic – Patent Ductus Arteriosus
• American Heart Association – Patent Ductus Arteriosus
• Centers for Disease Control and Prevention – Patent Ductus Arteriosus
• National Heart, Lung, and Blood Institute – Patent Ductus Arteriosus
• Children’s Hospital of Philadelphia – Patent Ductus Arteriosus