What is Atrial Septal Defect ?

Atrial septal defect is a common congenital heart disease characterized by a defective septum separating both atriums from each other due to an embryonic developmental defect, or an opening between the left and right atria to allow the passage of blood due to incomplete closure. The shunt is caused by right ventricular compliance and the direction of the shunt is left to right.

ASD What are the Causes of Atrial Septal (ASD) Defects?

ASD is the second most common congenital heart disease in childhood. Approximately 30-50% of children with congenital heart disease have ASD as part of their heart malformation. Approximately 70% of all ASDs are secundum type lesions and are seen 2 times more frequently in girls than in boys. ASD is reported in approximately 2 out of every 1000 live births. Most defects are isolated and occur sporadically. Atrial Septal defect has been reported as an isolated defect in 5-10% of all congenital heart diseases. ASD is the most common congenital heart anomaly in the adult age group. The reason for this is, The defect is overlooked because most patients do not have serious symptoms.

It is known that familial secundum defects have heterogeneous inheritance types, most of which are autosomal dominant. The risk of secundum defect increases, especially in families with a sibling with ASD and a history of congenital heart disease. On the other hand, diabetes mellitus, non-diabetic mothers with an increased glycemic index, and advanced maternal age (≥35 years) are other maternal risk factors that cause ASD. ASD types are divided into different subgroups according to the localization of the defect. In order of frequency, from most common to least common, It is classified into four groups as secundum, primum, sinus venosus and coronary sinus type. Apart from these, patent foramen ovale (PFO), which causes communication between the left and right atria, is not considered an atrial septal defect.

Atrial Septal Defect Symptoms and Diagnosis (ASD)

The majority of infant and pediatric patients with ASD are asymptomatic. The age at diagnosis is delayed in patients because the symptoms show late clinical signs and the physical examination findings do not attract the attention of the physician. Approximately ¼ of the patients are diagnosed after the first decade. Patients are usually diagnosed incidentally on echocardiography (ECHO) performed for a heart murmur on physical examination or for another reason.

Recently, there has been a decrease in the age of detection of ASD because infants with a heart murmur heard on physical examination are referred to pediatric cardiologists earlier. Asymptomatic patients without heart failure or pulmonary hypertension, but with weight or height (z) values <-1, were operated at an average age of 4 years, and z values increased by 0.5 within 2 years in the follow-up.

In cases with early diagnosis and timely intervention, the expectation is a normal life expectancy and quality. However, the life expectancy of patients who underwent surgery at an advanced age is shorter than that of patients of the same age. Most patients diagnosed with ASD are asymptomatic. Congestive heart failure may rarely develop in ASD cases during infancy.

If large defects are not treated, pulmonary hypertension and heart failure occur in adults (in the 20-30s). Atrial arrhythmias can be seen in these cases in adults. Infective endocarditis is not seen in isolated ASDs, so prophylaxis is not necessary in these cases. Bacterial endocarditis may develop in secundum type defects. Therefore, prophylaxis must be applied. Cerebrovascular events caused by paradoxical embolization are a rare complication in the pediatric age group.

Atrial Septal Defect Treatment (ASD)

Today, transcatheter closure of ASD cases has provided an alternative to open surgery. It was first successfully closed by King in 1976 with the secundum ASD ‘double umbrella’. Although there are many technological innovations in this regard, most of them are not practical. Among these, Amplatzer Septal Occluder came to the fore.

Amplatzer septal ocluder was approved in 2001 and Helex occluder was approved by Food and Drug Administration (FDA) in 2006. The natural course of ASD, It depends on patient factors, the anatomical type of ASD, and the size. In sinus venosus and primum-type lesions, the shunt is mostly hemodynamically significant and the size of the defect does not decrease and is often surgically closed. It has been stated that the probability of spontaneous closure of the ASD and the closure time are proportional to the shunt diameter determined by Echo performed before the third month of life. Since the defects may close spontaneously, the patient should be carefully evaluated before deciding on surgical repair before the age of two in cases with ASD.

Atrial septal defects of primum, sinus venosus, and coronary sinus character should be closed with surgical closure. Secundum-type atrial septal defects can be closed both surgically and percutaneously with a transcatheter closure device. Atrial septal defects of primum, sinus venosus, and coronary sinus character should be closed with surgical closure. Secundum-type atrial septal defects can be closed both surgically and percutaneously with a transcatheter closure device.