AVSD

Atrioventricular Septal Defect (AVSD) is a complex congenital heart defect that involves abnormalities in the structure of the heart’s atrial and ventricular septa, as well as its atrioventricular valves. This condition is characterized by a combination of several heart defects present at birth. The defects typically involve a hole between the heart's chambers and problems with the valves that regulate blood flow in the heart. AVSD affects the flow of blood through the heart, causing it to work harder and less efficiently.

Etiology and Pathophysiology

AVSD results from abnormal development of the embryonic heart during the first eight weeks of pregnancy. The exact cause of AVSD is not fully understood, but it is believed to involve a combination of genetic and environmental factors. In some cases, AVSD is associated with chromosomal abnormalities, such as Down Syndrome.

The defect leads to a combination of four heart abnormalities: an ostium primum atrial septal defect, a ventricular septal defect, a single atrioventricular valve instead of two separate valves (mitral and tricuspid), and abnormalities in the attachment of the atrioventricular valve leaflets.

Classification

AVSDs are classified into two main types based on the presence or absence of a ventricular septal defect:

• Complete AVSD: Both atrial and ventricular septal defects are present, along with a common atrioventricular valve.
• Partial AVSD: There is an atrial septal defect and anomalies in the atrioventricular valves, but the ventricular septum is intact.

Symptoms and Diagnosis

Symptoms of AVSD vary depending on the severity of the condition and may include difficulty breathing, fatigue, poor feeding and growth in infants, and frequent respiratory infections. Severe cases can lead to heart failure and pulmonary hypertension.

Diagnosis of AVSD typically involves a combination of physical examination, echocardiography, and sometimes cardiac MRI or cardiac catheterization. Echocardiography is the primary tool for diagnosing AVSD, as it can provide detailed images of the heart's structure and function.

Treatment

Treatment for AVSD depends on the severity of the condition and the presence of associated symptoms. In many cases, surgery is required to correct the defects. Surgical options include patch closure of the septal defects and reconstruction of the atrioventricular valves. The timing of surgery is determined based on the severity of symptoms and the degree of heart dysfunction.

Prognosis

The prognosis for individuals with AVSD has improved significantly with advances in surgical techniques and postoperative care. However, long-term outcomes depend on the severity of the defect, the presence of associated chromosomal abnormalities, and the success of surgical intervention. Regular follow-up with a cardiologist is essential for monitoring heart function and managing complications.

See Also

• Congenital Heart Defect
• Down Syndrome
• Heart Failure
• Pulmonary Hypertension