What Causes Ventricular Septal Defect (VSD) in Babies
Ventrucular Septal Defect or VSD is when there is a hole in the septum (the tissue ) seperating the left and right chambers of the heart called ventricles. As a result of this hole the oxygen rich blood coming in from lungs instead of going to the rest of the body mixes with the oxygen poor blood going to the lungs.
Based on the size and location of the hole in the ventricle, it could impact the funtioning of the heart by making it work harder and could increase the blood pressure in the lungs. Therefore it becomes imperative to see a pediatric cardiologist the minute you learn of your child's condition without delay.
Related: Congenital Heart Defects
Causes of Ventricular Septal Defect (VSD)
In most cases this congenital birth defect has no known cause. It could occur as a consequence of a genetic disorder or syndrome, environmental factors, medications the mother was on or could be mutations. Researchers don't know for sure as to what causes a congenital VSD. Acquired VSD could be a consequence of a heart attack or complications during one's lifetime that usually has a known cause.
Let us look in detail about the types of VSDs, how it impacts your child, treatment and long term prognosis.
Ventricular Septal Defects Types Based on Location
The septum is made up of muscle tissue and thin fibrous membrane tissue and based on the location of the hole they are categorized in to the below four types.
Membranous: VSD present in the upper membranous section of the septum. It is the most common type of VSD seen in almost 80% of cases.
Muscular: VSD in the lower muscular part of the septum, and could occurs as more than one hole as part of the heart defect.
Inlet: VSD occurs right below the tricuspid valve in the right ventricle and the mitral valve on the left, the entering blood into the ventricles through the valves mix through this hole.
Outlet: VSD occurs right below the pulmonary vein on the right and aortic artery on the left ventricle, the blood going out of the ventricles mixes through this hole.
Ventricular Septal Defects Types Based on Size
The size of the hole is crucial as larger the size the more it impacts the heart, lungs and overall quality of life and is one of the important factors in determining the need for surgery to correct the defect.
Small (up to 3mm): Majority of VSDs fall under this category and usually never have any symptoms. The hole closes on its own in 9 out of 10 cases without any medical intervention by the time the child is 6years of age.
Moderate (4mm to 5mm): These VSDs may or may not cause any symptoms, doctors wait and watch if no symptoms are seen in the heart, lungs or rest of the body as the VSD may close on its own as the child grows.
Large (6mm to 10mm): These VSDs often always cause symptoms and need constant evaluation by the cardiologist to monitor the progression. Surgery may be inevitable in case of large defects and is usually done below 2 years of age to prevent any permanent damage to the heart and lungs.
Ventricular Septal Defect Symptoms in Babies / Children
The healthy heart has four chambers that seal shut to prevent any spillage and mixing of blood, valves help with this containment and movement of the blood across the heart, towards lungs and rest of your body.
In case of VSD the oxygenated blood from the left ventricle mixes with deoxygenated blood in the right ventricles as pressure in left ventricle is higher, making the heart work harder and this also impacts the lungs as the amount of blood going to lungs from the right ventricle is now higher, this is called wet lungs and makes the patients more prone to respiratory infections.
Additionally you see the below symptoms in patients with moderate to large VSDs:
Sweating or fatigue during feeds or during moderate exercise in older kids
Slow or difficulty in gaining weight
Fast rapid breathing / struggling to breath
Frequent respiratory infections
Eisenmenger Syndrome: Develops when consistently the lungs get more blood increasing the lung pressure where the deoxygenated blood moves from the right ventricle to left oxygenated blood and goes to the rest of the body, as a result giving a blue tinge to skin, lips and few other parts. This is called cyanosis and if left untreated for long it permanently damages the lung and is called Eisenmenger syndrome.
Diagnosis of Ventricular Septal Defect (VSD)
If the VSD is very small as in most cases and shows no symptoms, its diagnosis could be difficult and usually goes unnoticed. In case of others the below methods are used.
During Pregnancy: The doctor performs an anomaly scan to see all whether all the major organs are developing as they should, In case of a large VSD the doctor could detect any issues with the heart and may ask for a foetal echocardiogram to assess the heart further.
After Birth: The baby with moderate to large VSDs may start showing symptoms within the first few weeks of life like fast breathing, sweating, difficulty to feed, etc. and the doctor may ask for an echo to confirm the same.
Physical Exam: Doctors may hear a murmur during physical exam and may ask for more tests to confirm. The murmur usually get obvious at around 3-6 weeks of age.
Tests done to diagnose VSD:
Echocardiogram - Most commonly used form of test as it uses sound waves to form the image of your heart and see the functioning. It is quick, painless, non-invasive and accurate and hence preferred form of testing.
Chest X-Ray - VSDs over time can cause structural changes to the heart which can be seen on x-rays, also wet lungs or excess blood in lungs can be seen. The technician may also inject a substance in the blood that highlights the circulation and any defects on the x-ray.
Electrocardiogram - or ECG uses multiple sensors stuck to your child's chest to measure electrical activity of the heart that shows up as a wave or graph on the screen that can be printed. Any structural changes or issues with the heart the wave pattern changes and helps doctors to assess the impact of VSD.
CT Scan - X-ray images of the chest / heart are processed by a computer to form a 3D image of the heart to see any structural changes or impact of VSD if any on the heart. An injectable substance is used to highlight on the screen and help with images.
Cardiac Catheterization - The doctor inserts the catheter device from your upper thigh into the major blood vessel to look in your heart to see for any defects. Not commonly used unless the doctor suspects a blood clot, blood vessel damage, high blood pressure in the lungs or an enlarged heart that needs a closer look.
Ventricular Septal Defect Treatment
Most VSDs close on their own as majority are small and don't cause any symptoms, may even go unnoticed. Moderate VSDs may cause symptoms and in any case the cardiologist would want to monitor the progress and take a call on way forward. Large VSDs in most cases need corrective surgery, they cause symptoms and may make it difficult for the child to thrive. The timing of the surgery and future course can only be decided by your child's doctor. Strictly follow everything your child's doctor asks you to do.
Surgery: Most reliable and often used method to close VSD is through surgery. The cardiac surgeon will open up the heart, close the hole using a patch or just stitch it up and seal the hole shut. Unless your child has other complications, for most surgeons VSD closure is a pretty straightforward and common procedure.
Trans Catheter Procedure: This method uses a transcatheter inserter in to the major blood vessel from your upper thigh to access your heart. Once inside the heart through the catheter a device made of a mesh is used to seal the hole shut.
Long Term Prognosis
Most kids post VSD closure go on to live healthy and normal lives. Your child may need to see the doctor for rest of their lives , which is more frequent post surgery and gradually reduces as your child grows up to once in few years.
Key is to keep your child physically active and healthy. Unless suggested by your doctor kids post VSD barring those few weeks to heal need no activity restrictions.