Adult Echocardiography Practice Exam

The ostium secundum atrial septal defect is the most common type of atrial septal defect. This condition occurs when there is a defect in the area of the septum where the foramen ovale is located, which usually closes after birth. In ostium secundum defects, there is an abnormal opening that allows blood to flow from the left atrium to the right atrium, leading to increased blood flow to the right heart and lungs. This type of defect is often asymptomatic in childhood, with symptoms becoming more apparent later in life, such as exercise intolerance, palpitations, or signs of heart failure due to volume overload. The prevalence of ostium secundum defects compared to other types of atrial septal defects contributes to its classification as the most common. In contrast, other variations like sinus venosus, ostium primum, and coronary sinus defects are less frequent. Sinus venosus defects are located near the entrance of the superior or inferior vena cava, ostium primum defects are associated with atrioventricular septal defects, and defects of the coronary sinus are rare occurrences involving the venous structures of the heart.