1) Disease Description (Causes and Symptoms)
Definition and Pathophysiology
- Atrioventricular septal defect (AVSD) is a congenital heart defect involving a defect in the atrioventricular septum (the atrial and ventricular septa) together with malformation of the atrioventricular (AV) valves (often a common AV valve or valve deformity).
- A left-to-right shunt from the left ventricle to the right ventricle/right atrium causes volume overload of the atria and ventricles and increased pulmonary blood flow, and may progress over time to pulmonary hypertension and heart failure. Causes
- Generally multifactorial (genetic predisposition + environmental factors). It is strongly associated with chromosomal abnormalities, particularly Down syndrome (Trisomy 21).
- Rarely, infection during pregnancy (e.g., rubella) or exposure to certain medications may be related. Main Symptoms
- Asymptomatic (in partial forms), tachycardia (atrial arrhythmia), shortness of breath, fatigue, feeding difficulties, poor weight gain (symptoms of heart failure in infants), and recurrent respiratory infections.
- Complete AVSD causes severe heart failure and pulmonary overcirculation early after birth. If treatment is delayed, it may progress to Eisenmenger syndrome (conversion to a right-to-left shunt due to increased pulmonary vascular resistance), resulting in an inoperable condition.
- Associated symptoms: a murmur and worsening heart failure due to AV valve regurgitation (particularly regurgitation of the mitral valve-like valve), and, in the long term, pulmonary hypertension and arrhythmias.
2) Treatment Methods and Precautions
Treatment Principles
- Treatment is determined by considering the type of defect (partial vs. complete), symptoms, pulmonary artery pressure, and associated abnormalities (e.g., Down syndrome). Non-Surgical Treatment
- Symptom control (heart failure medications such as diuretics and digitalis), nutritional management, and prevention and treatment of respiratory infections. Surgical Treatment (Standard)
- Definitive treatment consists of open-heart surgery to close the defect with a patch and repair (or replace) the AV valves (tricuspid- and mitral-type valves).
- For partial forms, surgery should be considered during childhood (recommended before 2–3 years of age) if symptoms or valve regurgitation are present.
- Early surgery is recommended for complete forms because pulmonary overcirculation and pulmonary hypertension can progress rapidly (usually within 6 months after birth; even earlier surgery is recommended, particularly for children with Down syndrome). Procedural Risks and Prognosis
- The surgical mortality rate is generally reported to be less than 2–3% (with differences depending on severity and underlying condition).
- AV valve regurgitation commonly remains after surgery, and severe mitral regurgitation may cause heart failure and require repeat surgery.
- Long-term management of pulmonary hypertension or arrhythmias may be necessary. Precautions (Self-Care and During Outpatient Visits)
- Because upper and lower respiratory tract infections may worsen heart failure, infection prevention (handwashing and vaccination) and early treatment are necessary.
- Monitor weight and feeding status before and after surgery, as well as worsening shortness of breath, cyanosis, or fatigue.
- Take medications regularly and monitor for adverse effects (such as electrolyte changes and effects on kidney function). Complications
- Valve regurgitation (particularly mitral regurgitation), pulmonary hypertension (surgery is not possible if it progresses to Eisenmenger syndrome), arrhythmias, and the need for repeat surgery.
3) Checklist Before an Outpatient Visit (Including Items to Bring, Records, and Example Questions)
Items to Bring (When Visiting the Hospital)
- A list of current medications (including doses and administration times)
- Previous test results (echocardiography (ECHO) report, cardiac catheterization results, and chromosomal test results, if available)
- Records of recent changes in weight and feeding amount, and records of fever or respiratory symptoms
- Vaccination records (particularly those related to respiratory infections) Symptom Checklist (Check Before the Visit)
- Shortness of breath (breathlessness during feeding, rapid breathing), decreased feeding amount, and poor weight gain
- Recurrent pneumonia/bronchitis or fever
- Cyanosis (lips, hands, or feet), fatigue or lethargy, and rapid heartbeat (tachycardia) Test Preparation
- Echocardiography (repeat testing is recommended if no recent test is available); if necessary, chest X-ray, electrocardiogram, oxygen saturation measurement, and cardiac catheterization (to assess pulmonary artery pressure and blood flow)
4) Examples of General Questions to Ask the Doctor
- What type of defect does this child have (partial or complete), and what is the current pulmonary artery pressure?
- When is surgery needed, and what type of surgery is expected? (e.g., patch repair + valve repair)
- What is the purpose of the medications currently being used, and what possible side effects do they have?
- What precautions should be taken in daily life before and after surgery (feeding, exercise, and vaccinations)?
- What is the long-term prognosis, and what is the plan for follow-up tests (echocardiography/electrocardiography/pulmonary artery status)?
5) Examples of Disease-Specific Questions
- (If Down syndrome is present) How does Down syndrome affect the timing of surgery and the risk of complications?
- How likely is mitral valve (or AV valve) regurgitation to remain after surgery, and what are the criteria for determining whether repeat surgery is needed?
(Reference Summary)
- AVSD is a congenital heart defect. Partial forms may be asymptomatic or cause symptoms later, while complete forms cause early heart failure and pulmonary hypertension; therefore, early diagnosis and treatment are important.
- Surgical repair is the definitive treatment. For complete forms, early surgery is usually recommended within 6 months after birth, and patients with Down syndrome have a greater need for earlier intervention.