Atrial septal defects

Atrial septal defects (ASDs) are the most likely congenital heart defect to be found in adulthood. They carry a significant mortality, with 50% of patients being dead at 50 years. Two types of ASDs are recognised, ostium secundum and ostium primum. Ostium secundum are the most common

• ejection systolic murmur, fixed splitting of S2
• embolism may pass from venous system to left side of heart causing a stroke

• associated with Holt-Oram syndrome (tri-phalangeal thumbs)
• ECG: RBBB with RAD

• present earlier than ostium secundum defects
• associated with abnormal AV valves
• ECG: RBBB with LAD, prolonged PR interval