The normal heart
The heart consists of four chambers – two upper filling chambers (atria) and two lower pumping chambers (ventricles). In between each atrium and ventricle is a valve that stops blood flowing backwards. There is also a valve where the pulmonary artery and aorta join the heart. The right and left sides of the heart are divided by a thick wall of heart muscle called the septum.
The function of the heart is to pump blood around the body. Blood comes into the right atrium from the body, through the tricuspid valve and into the right ventricle. From here, it is pumped up the pulmonary artery to the lungs to pick up oxygen. Oxygen-rich blood comes back to the heart through the pulmonary veins into the left atrium. It flows through the mitral valve into the left ventricle. This pumps the blood into the aorta and from there around the body.
What is total anomalous pulmonary venous return?
Normally the blood is pumped from the right lower pumping chamber (right ventricle) through the pulmonary artery to the lungs to pick up oxygen. It then returns to the heart through the pulmonary vein into the left atrium from where it reaches the left ventricle for pumping around the body.
In total anomalous pulmonary venous return the veins carrying red blood draining from the lungs reaches the ‘wrong’ atrium by some abnormal route.. This causes problems for the lungs which have to deal with high blood flows. There is a hole between the two collecting chambers of the heart (atrial septal defect) which is helpful as it allows blood to reach the left ventricle for pumping around the body.
What causes total anomalous pulmonary venous return?The heart is formed very early in pregnancy. We do not fully understand why some children’s hearts do not develop properly so have a congenital heart defect. We know that the chance increases if one or both parents had a congenital heart defect. Congenital heart defects can also be more common in children with other congenital conditions.
What are the signs and symptoms of total anomalous pulmonary venous return?Almost all babies with total anomalous pulmonary venous return become sick soon after birth. Breathlessness is the most common symptom and on checking, the baby’s skin and lips are also a little blue. Sometimes the abnormal veins are blocked as well as having an abnormal route and these babies can get very sick or collapse. Other babies without obstruction may be a little older before breathlessness interferes with feeding and the baby fails to thrive.
How is total anomalous pulmonary venous return diagnosed?
Doctors will use chest X-rays, electrocardiograms (ECG) and echocardiograms (Echo) to diagnose total anomalous pulmonary venous return. An ECG measures the electric current passing through the heart. An Echo is an ultrasound of the heart and shows not only the structure of the heart but the blood flow through it.
Children may also have a cardiac magnetic resonance imaging (MRI) scan, which uses a strong magnetic field, radio waves and a computer to form detailed pictures of the heart.
How is total anomalous pulmonary venous return treated?Total anomalous pulmonary venous return needs to be corrected in an open heart operation. The surgeons will connect the pulmonary veins to the ‘correct’ left filling chamber (atrium) and close the atrial septal defect.
What happens next?All children with congenital heart defects (even when corrected) will need regular check ups in hospital for a long time, usually continuing into adulthood. These will usually involve repeat Echo and ECG scans and sometimes cardiac magnetic resonance imaging (MRI) scans. The aim of these check ups is to monitor the child’s heart function so that any future heart problems are diagnosed and treated quickly.
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