Single ventricle means that one of two ventricles (lower chambers of heart) is very small in size.
Examples of single ventricle related congenital heart diseases are:
- Double inlet ventricle (commonly left ventricle)
- Heterotaxy syndromes (complex cardiac anomalies)
- HLHS (Hypoplastic left heart syndrome)
- Tricuspid atresia
- Few cases of double outlet right or left ventricles
Symptoms in single ventricle physiology
Symptoms due to single ventricle depend on whether there is narrowing in pulmonary artery present or not (pulmonary stenosis, PS).
- When there is no PS, then child will have signs of cardiac failure in the form of shortness of breath, poor weight gain etc.
- When there is severe PS, then child will have bluish discoloration of lips and fingers (cyanosis).
- Very rarely, baby may have balanced circulation in lungs (that is limited blood supply to both lungs); these babies will not require early treatment in newborn period.
Diagnosis of Single Ventricle
- Pediatric echocardiogram is required for diagnosing this anomaly.
- Occasionally, CT scan is also required when echocardiogram is not conclusive.
- Other investigations are ECG and chest x-ray.
- Sometimes, “diagnostic cardiac catheterization”needs to be done when echocardiogram/CT angiogram is not conclusive or when we have to determine whether child is operable or not.
Treatment of Single Ventricle
Treatment is by doing “Surgery” in most cases.
Mode of operation depends on type of single ventricle cardiac defect.
In first stage:
In cases of severe pulmonary stenosis/pulmonary atresia, a graft is placed between main blood vessel artery branch (branches of aorta: left subclavian or left innominate artery) to the pulmonary artery. This is known as BT shunt or we can palliate by doing stenting of patent ductus aretriosus (PDA stenting) instead of doing BT shunt.
When blood flow to the lungs is in excess then we put a band in main pulmonary artery (PA banding).
Other operations that we need to do in more complex cardiac problems like HLHS is known as Norwood Operation.
In second stage:
“Glenn shunt” has to be done that is a connection between superior vena cava and pulmonary artery with take down of BT shunt or PDA stent. This operation is done between 6 months to 1 year of age.
In third stage:
“Fontan operation” is recommended in which inferior vena cava is connected to pulmonary artery as well. It is done between 2-4 years of age.
Now a day, prognosis after doing third stage of operation is good as compared to previous years.
Pregnancy is a relative contraindication after doing all surgeries in single ventricle as carries high risk both to mother and baby.