What is the most common type of atrial septal defect?

The most common type of atrial septal defect is the secundum defect. This type occurs in the middle part of the atrial septum, where the foramen ovale is located. In secundum defects, there is a failure of adequate closure of the foramen ovale during embryonic development, leading to a communication between the left and right atria. This results in left-to-right shunting of blood, which can cause increased pulmonary blood flow and potentially lead to complications over time if left untreated.

Secundum defects can vary in size and may be asymptomatic in childhood, with symptoms often presenting later in life, such as palpitations, exercise intolerance, or signs of heart failure. The recognition of this defect is essential in cardiac imaging and ultrasound studies, as it is often the most frequently diagnosed congenital heart defect in adults.

Understanding the prevalence of secundum atrial septal defects is crucial for early detection and treatment, making it a vital point of knowledge for cardiac sonographers and healthcare professionals involved in cardiac care.