Atrial Septal Defect


ASDIs the most common congenital cardiac malformation in adults.

It can be of 3 kinds:

1. Sinus venosus defect

-it is located in the upper portion of the interatrial septum, close to the  vena cava. May cause abnormal pulmonary vein drainage into the right atrium.

 2. Ostium Secundum defect

-is met quite frequently (70-75%). Attention, because it should not be confused with patent foramen ovale.

 3. Ostium Primum defect

– in the upper portion of the septum

Atrial septal defect causes left to right shunt due to the high compliance of the right atrium and the difference in  pressure between the two atria. Secondary to this mechanism, the pressure in the pulmonary circulation is increased.

Clinically, the size of the shunt and the degree of pulmonary hypertension are variable. The patient may be completely asymptomatic or may present fatigue, exertional dyspnea, palpitations, poor stature-weight development. In case of patent foramen ovale, there is no shunt and paradoxical embolisms may occur.

The diagnosis is set especially after physical examination:

-at auscultation;

-low intensity systolic murmur can be distinguished in the pulmonary focus;

-the second heart sound is duplicated;

-short diastolic murmur at the tricuspid valve;

– apical systolic murmur (degree of mitral regurgitation due to cleft).

Atrial septal defect type Ostium Primum + anomaly of adiacent intraventricular sept + anomaly of the mitral valve, cause cleft. In time, pulmonary hypertension occurs, generating noise 2 emphasized, along with systolic pulmonary click and diastolic murmur of pulmonary insufficiency.  Overuse of the ventricle will cause systolic murmur at the tricuspid valve, which will be increased in inspiration, and protodiastolic or presistolic gallop.

Radiologically

It is highlighted

-extension of the right heart;

-swelling of the pulmonary artery;

-pulmonary circulation overcharged;

 Electrocardiographically

-major or minor blockage of the right branch;

-QRS axis deflected to the right in secundum type defect and left in ostium primum

Echocardiographicaly

-continuitity of the interatrial septum is highlighted best in 4 rooms section;

-injection of the contrast substance that will fill right cavities and will go also to the left;

– Valsalva maneuver and cough emphasizes communication.

Cardiac catheterization

-confirms the diagnosis by passing the probe through the septum, measures the shunt flows and the pressure in the pulmonary artery.

 Complications of the atrial septal defect

-pulmonary hypertension;

-right cardiac insufficiency

-increased frequency of atrial and ventricular arrhythmias;

-endocarditis.

Treatment

Surgical correction will be required when the pulmonary flow is grater when compared to the aortic flow. 2. If it is considered that the defect is small or the resistance in the pulmonary circulation is equal to the systemic vascular resistance, the defect will not be closed, as it would lead to right heart decompensation. In these situations calcium channel blockers are used.


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