Atrial Septal Defects

¨Second most common congenital lesion in adults (first most common:  bicuspid aortic valve)

¨Often asymptomatic until adulthood

¨Complications

¡Irreversible pulmonary hypertension

¡Right ventricular failure

¡Atrial arrhythmias

¡Paradoxical embolism

¡Cerebral abscess

¨Sinus Venosus ASDs

¡Often associated with partial anomalous pulmonary venous drainage of right upper and middle pulmonary veins

¨Secundum ASDs

¨Primum ASDs

¡Often associated with cleft anterior mitral valve leaflet

Partial Anomalous Pulmonary Venous Return (associated with sinus venosus ASDs)

Cleft Anterior Mitral Valve Leaflet (associated with primum ASDs)

Identification

¨Imaging must demonstrate presence and direction of shunting across defect with evaluation of associated anomalies

¨Echocardiography is primary imaging modality of choice

¨TTE is usually definitive in ostium secundum and primum defects

¨TEE is helpful in determining size of defects and identifying sinus venosus defects of SVC or IVC

Transthoracic Echo Identification

¨B-mode

¡Secundum and primum ASDs can be visualized

¡Clues include:

úAbrupt discontinuity of the septum

úThickening at its termination

úHypermobility of septum

¨Doppler

¡Color flow can confirm presence of ASD, estimate size, indicate direction of flow

¡Pulsed wave useful in assessing low velocity flows

¡Continuous –wave useful for assessing high velocity flows

Indications for ASD Closure

¨Primary Indication:  right ventricular enlargement irrespective of symptoms

¨Symptoms would include:

¡Exercise intolerance

¡Fatigue

¡Dyspnea

¡Heart Failure

¡Paradoxical Emboli

¡Arrhythmias

¨Also reasonable in patients with paradoxical embolism

¨Primum ASD closure is indicated at the time of cleft mitral valve repair

Contraindications to Closure

¨Irreversible, severe pulmonary hypertension

¡Reduced expected survival regardless of therapy

¡Maintenance of interatrial communication may provide mechanism to maintain cardiac output

Follow up

¨Patients with small ASDs (<10 mm) with no evidence of right ventricular enlargement or pulmonary hypertension can be regularly followed up with echocardiography every 2-3 years.