Atrial septal defect

An atrial septal defect initially presents with a what type of shunt?

An atrial septal defect initially presents with a left-to-right shunt.

A 12-year-old boy was diagnosed with an atrial septal defect (ASD). What would you expect to see on his ECG? A. Left ventricular hypertrophy (LVH) B. Right ventricular hypertrophy (RVH) C. Right bundle branch block (RBBB) D. Left bundle branch block (LBBB)

C. Right bundle branch block (RBBB) Almost all patients with an atrial septal defect will have an RBBB on their ECG. Left ventricular hypertrophy (LVH) can be seen on conditions such as a ventricular septal defect. Right ventricular hypertrophy and right axis deviation can be seen with tetralogy of Fallot. Left bundle branch block in pediatric patients can be seen in LVH, left ventricular noncompaction, and Wolff-Parkinson-White syndrome.

A 41-year-old male presents complaining of easy fatigability. On physical exam, a wide fixed split S2 and a Grade II/VI systolic murmur is heard over the pulmonic region. Which of the following will be most beneficial in the diagnostic evaluation? A. Obtain an ECG. B. Obtain a chest x-ray. C. Refer for cardiac catheterization. D. Refer for echocardiography.

D. Refer for echocardiography. Direct visualization of the atrial septal defect by two-dimensional echocardiography and demonstration of a left to-right shunt through the defect by color-flow Doppler confirms the diagnosis of atrial septal defect.

What is the etiology of atrial septal defect (ASD)?

During the embryological development of the heart, a septum grows toward the endocardial cushions to divide the atria. Failure of septal growth or excessive reabsorption of tissue leads to ASDs.

What is the best diagnostic tool for diagnosing atrial septal defect?

Echocardiography is the best diagnostic tool for diagnosing atrial septal defect.

How does ASD present clinically?

The pathophysiology and amount of shunting depending on the size of the defect and the relative compliance of the both ventricles. Even with large ASDs and significant shunts, infants and children are rarely symptomatic. A prominent right ventricular impulse at the left lower sternal border (LLSB) often can be palpated. A soft (grade I or II) systolic ejection murmur in the region of the right ventricular outflow tract with a fixed split S2 (due to overload of the right ventricle with prolonged ejection into the pulmonary circuit) are often audible. A larger shunt may result in a mid-diastolic murmur at the LLSB as a result of the increased volume passing across the tricuspid valve.

What is the epidemiology of ASD?

ASDs represent approximately 10% of all congenital heart defects.

What type of congenital heart disorder is an atrial septal defect?

Atrial septal defect is a non-cyanotic congenital heart disorder.

What complication of atrial septal defect results from a clot from a deep vein thrombosis?

A paradoxical embolus is a complication of atrial septal defect in which a clot from a deep vein thrombosis can cross over from the right heart to the left causing stroke. Or brain abscess if the embolus is septic.

What are the types of ASD?

A secundum defect, with the hole in the region of the foramen ovale, is the most common ASD. A primum ASD, located near the endocardial cushions, may be part of a complete atrioventricular canal defect or may be present with an intact ventricular septum. The least common ASD is the sinus venosus defect, which may be associated with anomalous pulmonary venous return.

Which of the following physical findings is suggestive of atrial septal defect? A. Fixed split S2 B. Increased pulse pressure C. Continuous mechanical murmur D. Difference in blood pressure between the left and right arm

A. Fixed split S2 An atrial septal defect will cause a shunt of blood from the left to the right atrium. This will result in an equalization in the amount of blood entering both the left and right ventricles which effectively eliminates the normally wide splitting that inspiration typically causes in hearts without an atrial septal defect.

Where are murmurs for ASD best heard? A. Second intercostal left sternal edge B. At the upper left sternal border and in the infraclavicular area C. The apex with radiation to the left axilla D. The second and third left intercostal space with radiation to the left shoulder

A. Second intercostal left sternal edge The murmur associated with ASD is heard best at the second intercostal left sternal edge.

What imaging studies can be used to diagnose ASD?

ECG and chest x-ray findings reflect the increased blood flow through the right atrium, right ventricle, pulmonary arteries, and lungs. The ECG may show right axis deviation and right ventricular enlargement. A chest radiograph may show cardiomegaly, right atrial enlargement, and a prominent pulmonary artery. Echocardiography - DEFINITIVE DIAGNOSIS will demonstrate a septal defect.

When is medical intervention indicated for ASD?

If a significant shunt is still present at around 3 years of age, closure is usually recommended. Many secundum ASDs can be closed with an ASD closure device in the catheterization laboratory. Primum and sinus venosus defects require surgical closure.

How is ASD treated?

Medical management is rarely indicated. Most small centrally located ASDs (< 3mm) close spontaneously; many defects between 3mm and 8mm close spontaneously by age 3 yr.

What are exam findings of ASD?

Widely split and fixed S2 into A2, Ps (lub, dub-dub). Murmur: grade II-III/VI systolic ejection murmur at left 2nd or 3rd intercostal space (pulmonic area).