Holes in the Heart
An atrial septal defect (ASD) is a congenital condition in which a hole is present between the 2 top chambers (atria) of the heart. ASDs may be present in various locations in the internal wall (septum) between the atria of the heart.
Small atrial septal defects may not cause any problems and may close on their own. Large or persistent atrial septal defects result in excess blood flow to the lungs and stretching/enlargement of the right side of the heart. This can lead to increased pressure in the arteries of the lung as well as heart failure.
An atrial septal defect is not usually associated with symptoms in childhood although sometimes it is associated with poor growth and frequent lung infections due to excess blood flow to the lungs. After the age of 30, symptoms such as fatigue, shortness of breath, heart palpitations and stroke can occur. ASDs can also be associated with abnormal connections of the veins from the lungs to the heart.
An atrial septal defect may be suspected by your child’s doctor if they hear a murmur while listening to the heart. A transthoracic echocardiogram (ultrasound) is performed to confirm the presence of an atrial septal defect. An ECG (electrocardiogram), chest X-ray, CT scan or MRI may also be performed.
Surgery to repair an atrial septal defect is usually recommended during childhood to avoid future problems. Sometimes the ASD can be closed using a device or plug inserted using a catheter guided through the leg vein. This is mostly for smaller ASDs. Larger ASDs or those with abnormal connections of the lung veins are closed using open heart surgery. The procedure involves use of the heart-lung machine and closure of the hole with a patch or directly with sutures. If the lung veins are abnormally connected they are redirected or reconnected at the same operation. The operation may be performed through a smaller incision than usual depending on the child’s age and size. The usual stay in hospital is about 5-7 days.
A ventricular septal defect (VSD) is a hole between the 2 pumping chambers of the heart. It results in excess blood flow to the lungs because blood flows through the hole from the high pressure left pumping chamber (left ventricle) to the lower pressure right pumping chamber (right ventricle) and through the lungs again before coming back to the left heart to repeat the cycle. This causes breathlessness, difficulty feeding and difficulty gaining weight due to increased work of breathing, and increased rates of chest infections.
VSDs occur in various locations in the internal wall between the two pumping chambers of the heart and vary in size; they can also be multiple in some cases. Surgery is required in the case of large VSDs or with VSDs in certain locations that are unlikely to ever close on their own. Many small to moderate size VSDs can be monitored over time and will gradually close as the child grows.
Surgical repair involves open heart surgery and use of the heart-lung machine. The hole is usually closed with a patch that is sutured in place. If there are multiple holes sometimes repair is delayed for a few months and a band is put on the lung artery to restrict blood flow into the lungs. This allows the baby to grow, some of the holes to close and an operation to be performed when the infant is larger. The long-term outlook following surgical closure of a VSD is very good and the likelihood of needing any further heart surgery in the future is often very low.
Atrioventricular septal defects (AVSDs) occur when the central part of the heart does not form correctly. They occur frequently in babies with Down’s syndrome but also in otherwise normal babies.
This abnormality includes a hole between the two top chambers of the heart called a primum atrial septal defect, a second large hole between the two pumping chambers of the heart called an inlet ventricular septal defect (VSD) and abnormal development of the two inlet valves of the heart where they are suspended over the central part of the heart. Instead of two separate inlet valves forming, a single large inlet valve forms that is suspended over both pumping chambers of the heart. An important part of the surgical repair involves dividing this one large valve into 2 separate inlet valves, one for the left heart and one for the right heart.
Atrioventricular septal defects have a wide anatomic spectrum. In some cases the VSD is either very small or absent. Children with this type of AVSD can often be repaired later in infancy or during childhood. Babies with very large VSDs, particularly with Downs’ syndrome usually require repair in the first 2-6 months of life.
The holes in the heart result in excess blood flow to the lungs, that causes breathlessness, increased rates of chest infections, difficulty with feeding and poor weight gain due to the increased work of breathing. Abnormal formation of the inlet valves can result in a leaky (regurgitant) left-sided inlet valve (mitral valve).
The procedure to repair an atrioventricular septal defect involves open heart surgery and use of the heart-lung machine. During the procedure the holes in the heart are closed, often using patches, and the single common inlet valve is dividing into 2 separate inlet valves by placement of these patches. The inlet valve on the left side of the heart then also requires closure of a gap or cleft between 2 of the 3 leaflets that form it. The stay in hospital after the procedure depends on the anatomy of the AVSD, the exact repair required and the child’s age. It ranges from 5 days to 3 weeks, including 1-4 days in the intensive care unit. About 10% of babies and children born with one of these abnormalities will require further surgery later in life due to abnormalities of the left inlet valve (mitral valve) and narrowing of the outlet of the left side of the heart that can develop subsequently.