Congenital aortopulmonary septal defect is a very rare birth defect of the heart. It is also called an aortopulmonary window. In this condition, there is an abnormal opening between the ascending aorta and the main pulmonary artery. Because the aorta has higher pressure, blood is pushed from the aorta into the lung artery. This sends too much blood to the lungs and makes the heart work harder. If the defect is not treated early, it can lead to heart failure, high pressure in the lungs, and permanent lung vessel damage. It is different from truncus arteriosus because the aortic valve and the pathway out of the right ventricle are formed separately. [MSD Manual]
Congenital aortopulmonary septal defect is also called aortopulmonary window. It is a rare birth defect of the heart where there is an abnormal opening between the aorta and the main pulmonary artery. Because the aorta has higher pressure, blood is pushed through this opening into the pulmonary artery, so too much blood goes to the lungs. Over time, this can cause fast breathing, poor feeding, poor weight gain, heart failure, pulmonary hypertension, and permanent lung vessel damage if it is not repaired early. The main treatment is early closure of the defect, most often with surgery, because medicines do not close the hole itself. [1]
Another names
Other names used for this defect are aortopulmonary window, AP window, aortopulmonary septal defect, and sometimes congenital aortopulmonary window. These names all describe the same basic problem: an abnormal connection between the aorta and pulmonary artery present from birth. [StatPearls]
Types
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Type I (proximal type): the opening is near the semilunar valves, in the first part of the great arteries. [StatPearls]
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Type II (distal type): the opening is farther away, near the pulmonary artery bifurcation. [StatPearls]
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Type III (total type): the defect is very large and combines features of the first two types. [StatPearls]
Causes
For this disease, doctors often speak more accurately about developmental causes, genetic influences, and pregnancy risk-linked factors. In many babies, the exact single trigger is not known. [CDC]
1. Failure of normal fetal separation of the great arteries: the main direct cause is incomplete formation of the septum that should divide the common outflow tract into the aorta and pulmonary artery. [StatPearls]
2. Abnormal conotruncal ridge fusion: the two ridges that help make the wall between the great vessels may not join properly, leaving a window. [StatPearls]
3. Early embryologic outflow tract maldevelopment: if the outflow tract develops abnormally very early in pregnancy, the defect can form before the heart is fully divided. [MSD Manual]
4. Sporadic developmental error: many cases happen without a clear family history or known outside cause, which means the change may occur by chance during heart formation. [Orphanet]
5. Genetic predisposition: some babies may have inherited or new genetic changes that increase the chance of congenital heart defects, including rare conotruncal defects. [MedlinePlus]
6. Family history of birth defects: having a close relative with a birth defect or congenital heart defect can raise risk in some pregnancies. [MedlinePlus]
7. Associated chromosomal or syndromic influence: rare heart defects may appear together with broader genetic syndromes or multiple structural problems, even when the exact syndrome is not found in every child. [Orphanet]
8. Maternal diabetes: uncontrolled diabetes before pregnancy or during early pregnancy is a known risk factor for congenital heart defects in general. [CDC]
9. Maternal obesity: pre-pregnancy obesity has been linked with increased risk of some major birth defects, including heart defects. [CDC]
10. Maternal smoking: smoking during pregnancy can increase the chance of birth defects and may contribute to abnormal fetal development. [CDC]
11. Alcohol use during pregnancy: alcohol exposure is a recognized risk factor for birth defects and can disturb normal fetal organ formation. [MedlinePlus]
12. Illicit drug exposure during pregnancy: use of street drugs in pregnancy is linked with increased birth defect risk. [MedlinePlus]
13. Certain medicines in early pregnancy: some medicines are suspected or known to increase birth defect risk when taken during the critical weeks of organ formation. [CDC]
14. Opioid pain medicine exposure: some studies have suggested a possible link between early pregnancy opioid exposure and selected birth defects. [CDC]
15. Trimethoprim-sulfamethoxazole exposure: this antibiotic has been listed by CDC among suspected drug exposures linked with some birth defects. [CDC]
16. SSRI antidepressant exposure: some reports have found possible associations between selective serotonin reuptake inhibitors and certain birth defects, though risk depends on the exact medicine and situation. [CDC]
17. Maternal fever or illness in early pregnancy: fever and some maternal illnesses can interfere with organ formation and are discussed as possible risk factors for some defects. [CDC manual]
18. Poorly controlled maternal medical disease: chronic illness in the mother, especially when poorly controlled, can affect fetal development and raise the risk of congenital problems. [MedlinePlus]
19. Coexisting major heart malformations during development: aortopulmonary window often appears with other heart defects, suggesting a broader developmental problem in the same stage of fetal heart formation. [StatPearls]
20. Unknown cause: for many babies, even after expert review, no exact outside cause can be identified. This is common in birth defects. [CDC]
Symptoms
1. Fast breathing: too much blood goes to the lungs, so babies may breathe quicker than normal. [MSD Manual]
2. Shortness of breath: the baby or child may look breathless during feeding, crying, or activity because the lungs are overloaded with blood flow. [MedlinePlus]
3. Poor feeding: infants may tire during feeding because the heart and lungs are working too hard. [MSD Manual]
4. Sweating with feeds: sweating, especially on the forehead during feeding, can be a sign of infant heart failure. [MSD Manual]
5. Poor weight gain: when feeding is hard and the body uses more energy to breathe, the baby may not gain weight well. [MedlinePlus]
6. Recurrent chest infections: extra blood in the lungs can make respiratory illness more common in some infants. [StatPearls]
7. Frequent tiredness: children may become tired easily because the heart is less efficient. [MSD Manual]
8. Rapid heartbeat: the heart may beat faster to keep up with the extra workload. [MedlinePlus]
9. Heart murmur: an abnormal blood flow sound is common and may be the first clue found by a doctor. [MSD Manual]
10. Enlarged liver from heart failure: in babies with congestive heart failure, the liver can become enlarged and feel below the ribs. [MSD Manual]
11. Irritability: babies may become fussy because feeding and breathing are difficult. [MedlinePlus]
12. Cyanosis in late or severe disease: a blue color of lips or skin may appear if pulmonary hypertension becomes severe and shunting changes direction. [MSD Manual]
13. Signs of pulmonary hypertension: older untreated patients may show worsening breathlessness, low exercise tolerance, or cyanosis from high pressure in the lung arteries. [MSD Manual]
14. Chest discomfort or palpitations in late presentation: adults with late diagnosis may report awareness of heartbeat or chest symptoms, though this is less common in infants. [PMC review]
15. Failure to thrive: this means the baby does not grow as expected because of chronic heart and lung strain. [MSD Manual]
Diagnostic tests
1. General inspection : the doctor watches the baby’s color, breathing rate, chest movement, and feeding effort. This can show heart failure or low oxygen. [MSD Manual]
2. Heart auscultation: the doctor listens with a stethoscope for a murmur and extra heart sounds caused by abnormal blood flow. [MSD Manual]
3. Respiratory exam: crackles, fast breathing, or signs of lung congestion may be present when there is too much blood flow to the lungs. [MSD Manual]
4. Growth and nutrition check : weight, length, and feeding history help show how much the defect is affecting daily health. [MedlinePlus]
5. Precordial palpation : the doctor places a hand over the chest to feel strong heart movement or a vibration from turbulent flow. [Cardiovascular exam]
6. Liver palpation : feeling an enlarged liver can support the diagnosis of heart failure in infants. [MSD Manual]
7. Peripheral pulse assessment : checking pulse strength and rate helps the doctor understand circulation and heart workload. [Cardiovascular exam]
8. Capillary refill and perfusion assessment : pressing on the skin and watching refill time gives a simple bedside clue about blood flow and circulation. [Cardiovascular exam]
9. Pulse oximetry : a sensor on the skin measures oxygen level. It helps detect low oxygen, especially in advanced disease. [MedlinePlus]
10. Electrocardiogram or ECG : ECG records the electrical activity of the heart and may show chamber enlargement or strain. [MSD Manual]
11. Arterial blood gas : this blood test measures oxygen, carbon dioxide, and acidity, and is useful in very sick infants or those with cyanosis. [MedlinePlus]
12. Complete blood count : this test is not specific for the defect, but it can check anemia, infection, or high hemoglobin in long-standing cyanosis. [MedlinePlus]
13. BNP or NT-proBNP : these heart stress markers may rise in heart failure and can support the clinical picture, although imaging is more important. [General heart failure testing]
14. Genetic testing : this may be used when doctors suspect a broader syndrome or multiple birth defects. [MedlinePlus]
15. Cardiac catheterization with hemodynamic study : a thin tube is passed into the heart and vessels to measure pressures, oxygen levels, and shunt size. It is especially useful when pulmonary hypertension is suspected. [StatPearls]
16. Transthoracic echocardiography: this is usually the main test. It uses ultrasound to show the opening and the abnormal blood flow between the aorta and pulmonary artery. [StatPearls]
17. Color Doppler echocardiography : Doppler adds color flow information, helping the doctor see the direction and speed of shunting. [StatPearls]
18. Chest X-ray : the X-ray may show an enlarged heart and increased blood flow in the lungs. [MSD Manual]
19. Cardiac CT angiography: CT gives a very clear picture of the opening and nearby blood vessels and is helpful in complex anatomy. [PMC CT review]
20. Cardiac MRI : MRI can define anatomy, shunt effects, and heart chamber size without radiation, although it is used less often than echo in small infants. [StatPearls]
Non-pharmacological treatments
1. Early surgical referral, 2. pediatric cardiology follow-up, 3. echocardiography monitoring, and 4. pulse oximetry and vital-sign monitoring are the first important non-drug steps. Their purpose is to confirm the defect, measure shunt size, check heart strain, and decide how fast repair is needed. Their mechanism is simple: careful monitoring finds worsening heart failure or rising lung pressure before permanent damage happens. These steps do not cure the opening, but they guide the life-saving timing of repair. [3]
5. Careful feeding plans, 6. frequent small feeds, 7. high-calorie nutrition plans, and 8. tube feeding when needed help babies who tire during feeding. The purpose is to improve growth and reduce energy loss. The mechanism is that babies with heart failure often burn more calories and get tired quickly, so giving smaller, more energy-dense feeds helps them gain weight and become stronger before surgery or during recovery. [4]
9. Oxygen support when clinically needed, 10. fluid balance monitoring, 11. daily weight checks, and 12. salt and fluid planning directed by the heart team are supportive therapies for children with congestion or breathing trouble. Their purpose is to reduce stress on the heart and lungs. The mechanism is that better oxygen delivery and careful control of fluid overload can reduce pulmonary congestion and help heart failure symptoms while the child waits for repair or recovers after repair. [5]
13. Infection prevention, 14. routine vaccination, 15. respiratory hygiene, and 16. avoidance of tobacco smoke exposure are important because chest infections can quickly worsen breathing and heart failure in infants with large left-to-right shunts. Their purpose is to lower illness burden and hospital visits. Their mechanism is reducing lung irritation, inflammation, and oxygen stress that can make pulmonary blood flow problems worse. [6]
17. Parent education, 18. activity pacing for older children, 19. postoperative rehabilitation and wound care, and 20. long-term surveillance for pulmonary hypertension or residual defects are also key. Their purpose is to help families notice danger signs early and support safe recovery after repair. Their mechanism is early detection of breathing trouble, poor feeding, cyanosis, fever, or exercise intolerance, so the medical team can act before severe complications appear. [7]
Drug treatments: what is evidence-based and what is not
There are not 20 FDA-approved drugs that specifically treat or close this defect. That would be misleading. The evidence-based drug approach is to use supportive cardiovascular medicines for selected patients with heart failure or pulmonary hypertension while the child is being stabilized for repair, or later if complications remain. [8]
Furosemide is a loop diuretic often used when fluid overload or pulmonary congestion is present. A common pediatric starting oral dose is often around 1 to 2 mg/kg per dose, but the exact dose and timing must be individualized by the treating specialist. Its purpose is to reduce extra fluid and improve breathing. Its mechanism is blocking sodium and chloride reabsorption in the kidney, which increases urine output. Important side effects include dehydration, low potassium, low sodium, kidney stress, and, at high exposure, ototoxicity. [9]
Spironolactone is a potassium-sparing diuretic sometimes added when ongoing fluid control is needed. A common pediatric range used in practice is often around 1 to 3 mg/kg/day, divided as directed by the cardiologist. Its purpose is to support diuresis and counter aldosterone-related salt and water retention. Its mechanism is aldosterone receptor blockade in the distal kidney. Key side effects include high potassium, dehydration, and sometimes breast swelling or tenderness. [10]
Digoxin may be used in some infants with heart failure symptoms when the team thinks stronger heart pumping support is useful. Pediatric dosing is weight-based and must be individualized carefully because the safety margin is narrow. Its purpose is symptom control, not defect closure. Its mechanism is increasing cardiac contractility and affecting electrical conduction through inhibition of the sodium-potassium ATPase pump. Side effects include slow heart rate, dangerous rhythm problems, nausea, vomiting, and toxicity if the dose is too high. [11]
Captopril and enalapril are ACE inhibitors sometimes used for afterload reduction in heart failure care. Dosing in children is individualized and started low. Their purpose is to reduce the work of the heart and improve forward blood flow. Their mechanism is blocking conversion of angiotensin I to angiotensin II, which lowers vasoconstriction and aldosterone activity. Common concerns are low blood pressure, kidney dysfunction, cough, and high potassium. [12]
Milrinone is an intravenous inotrope and vasodilator used in intensive care in selected severe cases, especially around surgery. Dose and infusion time are specialist decisions in monitored settings only. Its purpose is to improve cardiac output and reduce vascular resistance in short-term decompensation. Its mechanism is phosphodiesterase-3 inhibition, which increases intracellular cyclic AMP. Important side effects include low blood pressure and arrhythmias. [13]
Sildenafil may be considered only when pulmonary hypertension is present and the specialist judges it appropriate. Its purpose is not to fix the hole but to lower pulmonary vascular resistance in selected patients. Its mechanism is phosphodiesterase-5 inhibition, which increases nitric oxide signaling and relaxes pulmonary vessels. Side effects include headache, flushing, low blood pressure, visual symptoms, and drug interactions, especially with nitrates. [14]
Carvedilol is sometimes used in chronic heart failure care in selected patients, though it is not a routine disease-specific drug for aortopulmonary window. Its purpose is to reduce adrenergic stress on the heart. Its mechanism is beta-blockade with additional alpha-blocking effect. Side effects include slow heart rate, low blood pressure, dizziness, and worsening heart failure if started too fast or in the wrong setting. [15]
Other medicines may be used case by case, such as extra diuretics, pulmonary vasodilators, ICU vasopressors, pain medicines after surgery, or antibiotics if infection is present, but they are supportive choices based on the child’s condition, not standard curative drug therapy for the defect itself. [16]
Dietary molecular supplements
There is no supplement that closes this defect. Supplements should only be used if the cardiology or pediatric team thinks they are needed. The most evidence-based nutrition approach is adequate calories, protein, and correction of proven deficiencies, not “heart-curing” supplements sold online. [17]
1. Folic acid, 2. iron, 3. vitamin D, and 4. multivitamin/mineral formulas may be useful only when deficiency risk exists. Their purpose is to support growth, blood health, and general nutrition. Their mechanism is basic nutritional replacement: folate supports cell division, iron supports hemoglobin, vitamin D supports bone health, and multivitamins help cover poor intake. Doses must match age and lab results, because too much iron or vitamin D can be harmful. [18]
5. Zinc, 6. omega-3 fatty acids, 7. protein supplements, and 8. medium-chain triglyceride or calorie-dense formulas may be used in selected undernourished children. Their purpose is to support growth and feeding efficiency. Their mechanism is helping tissue repair, energy intake, and overall nutritional reserve, especially when a child tires during feeds. These are supportive nutrition tools, not direct treatments for the structural heart defect. [19]
9. Electrolyte replacement and 10. thiamine or other targeted vitamin replacement may be needed if a child is on diuretics or has laboratory-proven deficiency. Their purpose is to prevent complications from poor intake or fluid-loss therapy. Their mechanism is restoring normal body chemistry for heart and muscle function. They should be used under medical supervision because overcorrection can also be dangerous. [20]
Immunity booster,” regenerative, or stem cell drugs
At present, there are no FDA-approved immunity booster drugs, regenerative drugs, or stem cell drugs specifically for congenital aortopulmonary septal defect. Any clinic claiming to “regrow” or “seal” this defect with stem cells outside proper trials should be viewed with great caution. [21]
The six categories people often ask about are stem cell infusions, exosome products, cord blood cell products, growth-factor injections, immune booster injections, and regenerative heart cell products. For this defect, these are not standard evidence-based treatments. Their proposed mechanism is tissue repair or immune modulation, but for congenital structural heart defects like this one, available treatment remains mainly surgical, and regenerative use is still investigational in other congenital heart settings, not established here. [22]
Surgeries or procedures
1. Open surgical patch closure is the main treatment in many patients. The surgeon closes the abnormal opening with a patch, usually through cardiopulmonary bypass. It is done because the defect causes a major left-to-right shunt and can quickly lead to heart failure and pulmonary vascular disease. 2. Primary surgical closure may be possible in selected small defects without a large patch. 3. Transcatheter closure has been reported in selected anatomies at experienced centers, but it is not the standard choice for every patient. [23]
4. Repair of associated defects such as interrupted aortic arch or other congenital anomalies may be needed at the same operation because aortopulmonary window can occur with other heart defects. 5. Heart-lung or heart transplantation is not standard early treatment, but in rare end-stage, inoperable cases with severe irreversible damage, transplantation may be considered. These procedures are done only when ordinary repair is impossible or too late. [24]
Preventions
Aortopulmonary septal defect itself often cannot be fully prevented, because many congenital heart defects happen for reasons doctors do not completely know. Still, some risk-reduction steps before and during pregnancy are sensible: 1. preconception care, 2. folic acid 400 micrograms daily before pregnancy, 3. good diabetes control, 4. avoiding alcohol, 5. avoiding smoking and secondhand smoke, 6. reviewing medicines before pregnancy, 7. rubella protection, 8. avoiding harmful substances, 9. managing PKU if present, and 10. early prenatal care. These steps lower general congenital defect risk, even though they cannot guarantee prevention. [25]
When to see doctors
See a doctor urgently if a baby has fast breathing, sweating with feeds, poor feeding, poor weight gain, bluish color, unusual sleepiness, repeated chest infections, or signs of heart failure. After diagnosis, ongoing follow-up with a pediatric cardiologist is essential because delayed repair raises the risk of pulmonary hypertension and permanent lung vessel damage. [26]
What to eat and what to avoid
Helpful choices usually include 1. breast milk if possible, 2. formula as advised, 3. frequent small feeds, 4. calorie-fortified feeds when prescribed, 5. enough protein, 6. iron-rich foods when age-appropriate, 7. fruits and vegetables, 8. adequate hydration as directed, 9. low-salt planning if the doctor recommends it, and 10. dietitian-guided nutrition for poor growth. It is wise to avoid smoke exposure, unnecessary herbal products, high-salt processed foods, unsafe “heart cure” supplements, and overfeeding that worsens fatigue. The exact diet depends on age, symptoms, and fluid status. [27]
FAQs
1. Is it the same as a hole in the heart? It is a structural opening, but specifically between the aorta and pulmonary artery, not the usual septal holes inside the heart chambers. 2. Is it rare? Yes, it is one of the rarest congenital heart defects. 3. Can medicine close it? No, medicines do not close it. 4. What is the best treatment? Early repair. 5. Why is early repair important? To prevent heart failure and lung vessel damage. [28]
6. Can a baby feed poorly because of it? Yes. 7. Can it cause poor weight gain? Yes. 8. Can it cause pulmonary hypertension? Yes. 9. Can adults have it? Rarely, if it was missed or untreated. 10. Is surgery usually successful? Early diagnosis and repair generally offer the best outcome. [29]
11. Are supplements enough? No. 12. Are stem cells proven for it? No. 13. Does every patient need the same medicines? No, drug choice depends on symptoms and complications. 14. Can the child live well after repair? Many children do very well with proper follow-up. 15. Is lifelong follow-up needed? Often yes, because repaired congenital heart disease still needs surveillance. [30]
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The article is written by Team RxHarun and reviewed by the Rx Editorial Board Members
Last Updated: March 05, 2025.
