Atrial septal defect
Atrial septal defect (ASD) are abnormal openings in wall separating brhe right and left atria.
Types of Atrial septal defects
1. Ostium secundum defect
Abnormal opening present in middle of atrial septum.
2. Ostium primum defect
Defect located in septum just above the tricuspid valve and is associated with a cleft in Mitral valve and defects of atrioventricular septum.
3. Sinus venosus defect
Abnormal opening at top of atrial septum. Opening may located adjacent to superior Vena Cava.
Abnormal connection of right pulmonary vein to right atrium or right superior venacava.
4. Coronary sinus defect
Absence of common wall that separates coronary sinus and left atrium.
Pathophysiology of Atrial Septal Defect
A defect cause communication between right and left atrium.
Oxygenated blood in left atrium is under high pressure, it forced through the defect into right atrium.
Left to right shunting of blood places burden on right side of heart, leading to increased pulmonary blood flow.
This shunting of blood does not produce cyanosis.
It leads to pulmonary congestion and right ventricular enlargement.
Clinical features of Atrial Septal Defects (ASDs)
1. Children with secundun and sinus venous atrial septal defects, are usually asymptomatic.
2. Rearely Congestive heart failure ( CHF)
3. Only symptoms- decrease excercise tolerance and dyspnea
Diagnostic Evaluation
1. Cardiac Examination
systolic ejection murmur
If left to right shunt large - diastolic murmur of increased blood flow across tricuspid valve heard.
2. Electrocardiogram
Right ventricular volume overload
3. Chest radiograph
Enlargement of heart and increased pulmonary vascular marking.
4. Echocardiogram (2D echo)
Location and size of atrial septal defect, dilatation of atria.
Therapeutic Management
1. Small arterial defect, usually close , requiring no intervention.
2. Surgical correction for hemodynamically significant atrial septal defect (between 2-4 years of age).
3. Median sternotomy and cardiopulmonary bypass
4. Small atrial septal defect
Purse string closure done by stitching around the opening and pulling it closed.
5. If atrial septal defect large
Knitted Dacron patch sewn over defect.
Post - Operative Complication
1. Cardiac enlargement
2. Dysrhythmias, irregular heartbeat
3. Infective Endocarditis
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