Usually picked up through antenatal scans or newborn examinations

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.

Pathophysiology

• Caused by defects in the formation of the atrial septum in utero (weeks 4,5) - leading to the formation of a shunt = blood flows from L to R atrium due to higher pressure in L side
• As blood continues to flow to lungs - patient DOES NOT become cyanotic, however increased flow to right side of heart = overload and right sided strain causing right sided heart failure and pulmonary hypertension
• Eventually this leads to Eisenmenger syndrome - where pulmonary pressure>systemic pressure reversing the shunt from right to left across the ASD
  • blood bypasses the lungs and patient becomes CYANOTIC

Types of ASDs:

• ostium secundum (70% of ASDs) - septum secondum doesnt close (hole in the wall)
• ostium primum - septum primum doesnt close (atrioventricular septal defect)
• patent foramen ovale - not strictly classified as an ASD

PC

May be asymptomatic in childhood and present later with:

• dyspnoea
• heart failure
• stroke

On examination:

• ejection systolic murmur, loudest at upper left sternal border
  • a fixed split second heart sound - hear the closure of the aortic and pulmonary valves at slightly different times (takes longer for R ventricle to empty)