Complete Atrioventricular Canal (AV Canal) Defect

Introduction

Complete Atrioventricular Canal (AV Canal) Defect is a serious congenital heart condition that affects the structure of the heart and its ability to efficiently circulate blood. It is characterized by a large hole in the center of the heart that affects both the atrial and ventricular septums, along with abnormal development of the heart valves.

Anatomy and Pathophysiology

In a normal heart, the atrial septum separates the left and right atria, and the ventricular septum separates the left and right ventricles. Additionally, the mitral and tricuspid valves regulate blood flow between the atria and ventricles. In complete AV Canal Defect: - There is a large atrioventricular septal defect (AVSD), meaning a hole exists in both the atrial and ventricular septa. - A single common atrioventricular valve replaces the two separate mitral and tricuspid valves, which does not function properly, leading to mixing of oxygenated and deoxygenated blood. - This condition results in excessive blood flow to the lungs, leading to pulmonary overcirculation and heart failure if untreated.

Symptoms

Common symptoms of complete AV Canal Defect include: - Rapid breathing (tachypnea) - Poor feeding and failure to thrive - Frequent respiratory infections - Cyanosis (bluish discoloration of lips and skin in severe cases) - Signs of heart failure such as excessive sweating and fatigue

Associated Conditions

Complete AV Canal Defect is commonly associated with genetic syndromes, especially Down syndrome (Trisomy 21). Other congenital heart defects may co-exist, making surgical repair more complex.

Diagnosis

The following diagnostic tools help confirm the condition:

1. Echocardiogram (ECHO): The primary tool for visualizing the defect.
2. Electrocardiogram (ECG): May show signs of heart enlargement and conduction abnormalities.
3. Chest X-ray: Shows an enlarged heart and increased blood flow to the lungs.
4. Cardiac catheterization: Occasionally used for detailed hemodynamic assessment.

Treatment

Surgical correction is the definitive treatment and includes:

1. Patch closure of the septal defect.
2. Valve repair or replacement of the malformed common valve.
3. Pulmonary artery banding (in some cases, as a temporary measure before full surgical repair).

Prognosis

With timely surgical repair, most patients achieve good outcomes. However, lifelong cardiac follow-up is necessary to monitor valve function and potential complications such as arrhythmias or residual heart defects.

Conclusion

Complete AV Canal Defect is a serious congenital heart disease that requires early diagnosis and prompt surgical intervention. Advances in pediatric cardiac surgery have significantly improved survival rates and quality of life for affected individuals.

Source recommendations

1. American Heart Association Guidelines

1. https://professional.heart.org/en/guidelines-and-statements
2. https://www.heart.org/
3. https://professional.heart.org/en/guidelines-statements
4. https://cpr.heart.org/en/resuscitation-science/cpr-and-ecc-guidelines
5. https://www.heart.org/en/healthy-living/fitness/fitness-basics/aha-recs-for-physical-activity-in-adults

2. European Society of Cardiology Guidelines

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines
2. https://academic.oup.com/eurheartj/article/42/34/3227/6358713
3. https://www.escardio.org/Guidelines
4. https://academic.oup.com/eurheartj/article/44/39/4043/7238227
5. https://www.escardio.org/