Atrial septal defect ostium primum overview

# Overview
An ostium primum defect  usually occurs due to the failure in fusion of the septum primum with the endocardial cushion. This defect is commonly associated with other cardiac anomalies in the septum such as ventricular septal defect, mitral valve cleft, pulmonary stenosis, subaortic stenosis, left superior vena cava, coarctation and  atrioventricular septal defect. The abnormalities of the atrioventricular valves include the cleft mitral valve, and the single atrioventricular valve (a single large, deformed valve that flows into both the right ventricle and the left ventricle). It is often associated with Down's syndrome.

# Anatomy
Ostium primum defects usually occur due to the failure in fusion of the septum primum with the endocardial cushion.

# Diagnosis

## Echocardiography
Echocardiography is the preferred diagnostic tool in the evaluation of an atrial septal defect. In general, an atrial septal defect patient will present symptomatic evidence of hemodynamic disruptions between the left and right atrium. Other more specific characteristics exist in echocardiography to identify various classifications of atrial septal defects.

# Treatment

## Medical Therapy
Definitive treatment of atrial septal defect involves surgical closure of the defect. Medical therapy has a limited role in the management of ASD, and is often used to manage complications like arrhythmia, congestive heart failure and other comorbidities associated with atrial septal defects such as stroke and migraine.

## Indications for Surgical Repair in Adults
The decision to surgically close an atrial septal defect depends upon many contributing factors including the type of defect, the size of defect, the amount of left-to-right shunting, the development or worsening of symptoms, the presence of pulmonary hypertension and the presence of any associated anomalies.

## Surgical Closure
Surgical closure is the commonest treatment method for atrial septal defect and has been the gold standard for many years. Many surgeons prefer more minimally invasive techniques over the conventional sternotomy to avoid potentials for additional complications. Special consideration must be taken into account for the age of the patient and the size of the defect involved. Surgical closure is indicated for patients with primum, sinus venosus and  coronary sinus type of atrial septal defects. However, ostium secundum atrial septal defects are commonly treated by percutaneous closure. With uncomplicated atrial septal defect, (without pulmonary hypertension and other comorbidities) the post-surgical mortality is as low as 1%.

## Percutanous Closure
Percutaneous device closure is commonly performed to close an ostium secundum type of atrial septal defect and patent foramen ovales. It is still not FDA approved for closure of other forms of atrial septal defects such as primum, sinus venosus and  coronary sinus. With proper patient selection at experienced centers, it has been found to be as successful, safe and effective as surgical closure.  Additionally, it has been associated with fewer complications and a reduced length of stay compared to  surgical closure.