Complications of Heart Defects


Congenital heart defects, for the most part, are not life-threatening; however, what makes them deadly is the complications that often occur as a result of poor blood flow in the internal organs and extremities, abnormal blood flow within the heart and the strain that the heart muscle experiences due to it.

Problems with Development

complications of heart defects

The development of the majority of children with serious congenital heart defects is usually slowed down. For example, they might start walking and talking much later than usual. These children also often have problems with physical coordination for the rest of their lives.

Children with serious congenital heart defects might also have trouble learning. This can be attributed to the fact that the brain did not receive enough oxygen during its most important development stages. Intelligence of the children, in most cases, is unaffected; however, some children perform well below expectations due to the following reasons:

  • Poor memory
  • Difficulty concentrating and low attention span
  • Problems understanding the speech of others
  • Problems expressing themselves through speech
  • Poor impulse control (acting without thinking of the consequences)
  • Poor planning abilities

Recent research has shown that children with major congenital heart defects who were treated using surgery still developed problems understanding a concept; this is known as a Theory of Mind (TOM).

TOM is the ability of people to understand the mental state of others. To understand that others have their own beliefs, intentions, desires, perspective, emotions, likes and dislikes. In essence, TOM is the ability of a person to view the world through the eyes of another.

Inability to see the mental state of others can lead to serious behavioral problems and problems with social interactions.

Respiratory Tract Infections

Due to poor blood flow within the lungs, the ability of the immune system to resist various pathogens that enter the airways is compromised. Children with congenital heart disease which results in congestive heart failure are much more likely to have pneumonia and other diseases of the respiratory tract. The usual symptoms of respiratory tract infection include:

  • Cough – can range from mild to severe
  • Rapid breathings
  • Wheezing


Congenital heart disease is also a major risk factor for developing endocarditis. The bacteria are more likely to attach themselves to the poorly developed valves of the heart. If not treated, endocarditis is a life-threatening disease.

Endocarditis usually develops due to infection in another part of the body (e.g. gums, skin, etc.), which then causes the bacteria to spread throughout the blood. Gum disease is a major risk factor for developing endocarditis in people with congenital heart disease. This is why people with heart defects must take excellent care of their gums and teeth. Also, people with heart defects are advised against having body piercings or tattoos.

Common symptoms of endocarditis include:

  • Febrile body temperature (38 degrees Celsius and above)
  • Loss of appetite
  • Chills
  • Night sweats
  • Muscle and join pain
  • Headache
  • Persistent cough
  • Shortness of breath

Pulmonary Hypertension

Some heart defects can cause the blood pressure within the bronchial circulation system to rise, as the left part of the heart fails to efficiently pump the blood. This leads to the pooling of blood within the lungs which causes pleural effusions (accumulation of fluid in the pleural cavity) and pulmonary edema (accumulation of fluid in the alveoli which impairs the gas exchange and can possibly cause respiratory failure).

Common symptoms of pulmonary hypertension include:

  • Extreme tiredness
  • Shortness of breath
  • Dizziness and feeling faint
  • Rapid heartbeat
  • Chest pain with no radiation.

Heart rhythm problems

Abnormal heartbeat in adults with congenital heart defects is relatively common. The most common type of arrhythmias in such circumstances is atrial fibrillation and flutter. During both of these conditions, the heart muscle is contracting too quickly to efficiently pump the blood. The most common treatment for this condition is implantation of a pacemaker, since atrial fibrillation is a life-threatening condition.

Heart Failure

Heart failure is a condition during which the heart is unable to pump the blood efficiently, which results in poor blood flow throughout the body. This condition can appear right after the baby is born (if the heart defect is very severe), or it can develop overtime if the heart defect is not treated. Heart failure leads to a vast number of conditions the most serious of which are pulmonary hypertension (as it can result in respiratory failure) and congestive hepatopathy (which can lead to liver failure).

The most common symptoms of heart failure include:

  • Breathlessness the extent of which depends on the level of heart failure
  • Extreme weakness and tiredness
  • Swelling of feet, legs, and abdomen

Blood Clots

Congenital heart defects increase the likelyhood of blood clot formation. These blood clots can then travel through the arteries causing embolism which can lead to:

  • Stroke – when a thrombus that was formed in the left side of the heart dislodges and travels through the arteries into the brain causing an obstruction in the blood flow. This type of stroke is known as ischemic stroke, since it is caused by severe ischemia (lack of oxygen), rather than by hemorrhage (spilling of blood), which causes hemorrhagic stroke.
  • Embolism of peripheral arteries – thrombi that originated in the left side of the heart are also very likely to travel to legs and feet which causes necrosis of the affected tissues.
  • Pulmonary embolism – this condition happens when the thrombus is formed in the right side of the heart. The dislodged thrombus can then embolize a small artery of the lung causing a pulmonary infarction (necrosis of a part of a lung which then leads to the formation of abscess).

Sudden Cardiac Death

It has been estimated that 0.1% of adults with congenital heart disease die from sudden cardiac death every year. In some cases a sudden arrhythmia (atrial or ventricular fibrillation) is the cause. In other cases the person might not have an arrhythmia prior to death. Therefore, identifying the people with a higher risk of having a sudden cardiac death presents a challenge.


The prognosis can vary greatly depending on the type of congenital heart defect and its severity. Children who quickly receive correct diagnosis and are appropriately treated have the best chances of survival. With implementation of more sophisticated technologies the prognosis for babies with congenital heart disease is constantly improving.

Children who have a mild heart defect and do not require surgery still have to be monitored by cardiologist all their life in order to quickly spot any possible complications.

Some defects are very hard to spot at birth and only become apparent later in life, causing a disability as the person ages. This is why it is important to have yearly medical check-ups from childhood to adulthood.


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