Atrial Septal Defect (Asd)

(Ostium secundum defect)

In an atrial septal defect (ASD) is one or more openings in the inter-atrial septum, which can cause a left-right shunt and volume overload in the right atrium or the right ventricle. Children are rarely symptomatic, but can have long-term complications after the age of 20 years. These include pulmonary hypertension, heart failure and atrial arrhythmias. Adults and, more rarely, adolescents may have exertional fatigue and atrial arrhythmias. A light mittsystolisches noise at the upper left sternal with a wide and fixed division of the second heart sound (S2) is typical. The diagnosis is made by echocardiography. Treatment consists of a transcatheter device closure or surgical removal.

Atrial septal defects (ASD) occur in 6-10% of congenital heart defects. Most cases are isolated and sporadic, but some can also be genetic in origin (z. B. mutation on chromosome 5, Holt-Oram syndrome).

In an atrial septal defect (ASD) is one or more openings in the inter-atrial septum, which can cause a left-right shunt and volume overload in the right atrium or the right ventricle. Children are rarely symptomatic, but can have long-term complications after the age of 20 years. These include pulmonary hypertension, heart failure and atrial arrhythmias. Adults and, more rarely, adolescents may have exertional fatigue and atrial arrhythmias. A light mittsystolisches noise at the upper left sternal with a wide and fixed division of the second heart sound (S2) is typical. The diagnosis is made by echocardiography. Treatment consists of a transcatheter device closure or surgical removal. Atrial septal defects (ASD) occur in 6-10% of congenital heart defects. Most cases are isolated and sporadic, but some can also be genetic in origin (z. B. mutation on chromosome 5, Holt-Oram syndrome). Classification ASD can be classified according to location: ostium secundum: a defect in the fossa ovalis – in the center (or center) of the atrial septum venous sinuses: a defect in the rear of the bulkhead near the superior vena cava or the inferior vena cava and often associated with an abnormal reflux of the upper or lower right pulmonary veins into the right atrium or vena cava into the ostium primum: a defect in the anteroinferior septum, a form of AV septal (Endokardkissen-) defect (Atrioventricular canal). Pathophysiology In order to understand the hemodynamic changes in ASD and other abnormalities should be the normal pressure conditions visualize (Normal blood circulation with representative right and left heart pressures (in mm Hg).). Normal blood circulation with representative right and left heart pressures (in mm Hg). Representative O2 saturation of the right heart = 75%; representative O2 saturation of the left heart = 95%. Right ventricular pressures are medium pressures. AO = aorta; IVC = inferior vena cava; LA = left atrium; LV = Left ventricle; PA = pulmonary artery; PV = pulmonary veins, RA = right atrium; RV = right ventricle; SVC = superior vena cava. When ASD it comes first to a left-right shunt (atrial septal defect.). Some small ASD, often oval, an elongated, patent foramen, close spontaneously during the first years of life. Persistent moderate to severe ASD cause large shunts, resulting in volume overload of the right atrium and ventricle. If they are not repaired, these shunts may lead to pulmonary hypertension, increased pulmonary vascular resistance and right ventricular hypertrophy, when the people aged between 20 and 30 years old. Atrial arrhythmias such as supraventricular tachycardia (SVT), atrial flutter or atrial fibrillation may also occur later. Ultimately, an increase in pulmonary artery pressure and vascular resistance leading to a bidirectional atrial shunt with cyanosis in adulthood (Eisenmenger’s syndrome). Atrial septal defect. The pulmonary blood flow and volume in RA and RV are increased. (Note: The intracardiac pressures remain during childhood usually within the normal range). With a large defect RA and LA pressures are equal. AO = aorta; IVC = inferior vena cava; LA = left atrium; LV = Left ventricle; PA = pulmonary artery; PV = pulmonary veins, RA = right atrium; RV = right ventricle; SVC = superior vena cava. Symptoms and signs Most patients with small ASD are asymptomatic. Large shunts may trigger exertional dyspnea, fatigue and atrial arrhythmias with palpitations. Microembolisms from the venous side of the circulation via ASD (so-called paradoxical emboli) can, often with atrial arrhythmias that cause cerebral or systemic thromboembolic events such as stroke. Rarely causes of ASD, undiagnosed or untreated, to a Eisenmenger syndrome. Auscultation shows typically a 2-3 / 6 mittsystolisches murmur and a fixed split S2 at the upper left sternal in children. A large left-right shunt can cause a low diastolic murmur (due to flow across the tricuspid valve) on the lower Sternalrändern. These findings may be absent in infants, even in the presence of a serious defect. A right cardiac pulse can manifest itself as a parasternales lifting. Diagnostic x-ray thorax and ECG echocardiography The diagnosis is made by cardiac examination, chest x-ray and ECG, and confirmed by two-dimensional Farbechokardiographie with Doppler sonography. In a large shunt the ECG shows an axis shift to the right, a Rechtshypertrophie or a right bundle branch block (RSR ‘in V1). The chest X-ray photographs show an enlarged heart with dilation of the right atrium and right ventricle, pulmonary artery, a prominent and increased pulmonary vascular drawing. A cardiac catheterization is only required when a transcatheter closure of the defect is planned. Treatment observation closure by a transcatheter or surgical intervention Most centrally located ASDs (<3 mm) close spontaneously. Some defects, which are between 3 mm and 8 mm, can take before 3 years of age. These defects likely to provide an expanded patent foramen ovale is instead real secundum ASDs. Ostial primum- and sinus venosus defects not close spontaneously. Asymptomatic children with a small shunt should be examined by echocardiography only periodically. Although in theory there is a risk of a paradoxical systemic embolism in these children, this event is rare in childhood. Therefore, it is not customary to include a small hemodynamically insignificant defect. Moderate to large ASDs (evidence of right ventricular volume overload on echocardiography) should be closed, usually between the ages of 2 and 6 years. The work can be considered in children with chronic lung disease formerly considered. A catheter lock with various devices (e.g., B. AMPLATZER® or Gore HELEX® Septal Occluder) can be carried out, if appropriate anatomical features are present such. B. sufficiently large edges of the septal tissue and a sufficient distance to vital structures such. B. aortic root, pulmonary, tricuspid valve. Otherwise, surgical intervention should be carried out. Defects of the sinus venosus and ostium primum (AV septal type) are not suitable for a closing by Katheterizierung. When the ASD is eliminated in childhood, the perioperative mortality rate is equal to 0 and the life expectancy corresponds to that of the normal population. Endocarditis prophylaxis is not necessary before surgery, but probably in the first 6 months after surgery or when a residual defect in addition to the operated site is available. Key points An atrial septal defect (ASD) is an opening in one of several parts of the Zwischenvorhofseptums that causes a left-right shunt. Small atrial communications include often spontaneous, but more do not, which leads to an overload in the right atrium and ventricle and ultimately to pulmonary hypertension, increased pulmonary resistance ventricular and right ventricular hypertrophy. In addition, SVT, atrial fibrillation or atrial fibrillation may occur. ASDs may allow emboli from the veins to enter the systemic circulation (paradoxical embolism), which leads to arterial occlusion (eg., Stroke). Auscultation shows typically a 2-3 / 6 mittsystolisches murmur and a fixed split S2; These findings may be absent in infants. Moderate to large ASDs should, if possible, be closed with a transcatheter device, usually aged 2 to 6 years.

Health Life Media Team

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