Hypoplastic left heart syndrome is a congenital heart defect marked by severe underdevelopment of the left side of the heart. The condition is complex and rare in occurrence.

In babies with hypoplastic left heart syndrome, the left side is not so effective in pumping blood to different areas of the body. Hence, the right side of the heart has to compensate for it and work harder to pump blood across the body as well as to the lungs.

Treatment of hypoplastic left heart syndrome involves the use of medicines to prevent the ductus arteriosus, i.e., the connection between the left and right side of the heart, from closing. Later, doctors may either perform a heart transplant or a heart surgery to correct the defect. Due to the numerous advancements in medical care, infants with hypoplastic left heart syndrome have a better rate of survival and prognosis as compared to the past.

Symptoms

Newborns with an underlying case of hypoplastic left heart syndrome typically fall very ill just after delivery. Some of the common signs and symptoms of hypoplastic left heart syndrome are listed below:

• Breathing difficulties
• Rapid breathing
• Cyanosis, i.e., the skin may elicit a grayish-blue hue
• Feeding problems
• Babies may be inactive, lethargic, and abnormally drowsy
• The feet and hands may feel cold to touch.

If the normal connections between the right and left sides of the heart in babies affected by hypoplastic left heart syndrome are allowed to shut, then the infant may suffer from shock and may eventually die. Some of the signs and symptoms of shock are as follows:

• A rapid, weak pulse
• The skin may feel clammy or cool to touch. It may be grayish or pale
• The pupils are dilated
• Breathing is abnormal; it may be shallow or slow, or it may be very fast.
• Dull eyes that look like a stare.

It may be noted that babies in shock may be either unconscious or conscious. It is a serious situation needing emergency medical care.

Causes

The cardiac defect associated with hypoplastic left heart syndrome develops during the growth of the fetus during the stage of heart development. Doctors are not aware of the causes of the development of such a defect. However, if one child in the family is afflicted by the condition, then the unborn baby will have increased risk to developing hypoplastic left heart syndrome.

A healthy heart consists of 4 chambers, two are located to the left and the other two towards the right. The main job of both the sides of the heart is to pump blood to different areas of the body; but each side is attuned for varying tasks. The right side of the heart transfers blood to the lungs where it gets enriched with oxygen and comes back to the left side of the heart. The left side then pumps blood into the aorta which transfers the oxygen-rich blood throughout the body.

Hypoplastic left heart syndrome is marked by absence or underdevelopment of the left ventricle or the lower left chamber of the heart. This results in inefficient pumping of blood and deficient blood supply to the body. Also, the mitral valve and the aortic valve located on the left side of the heart do not work effectively. The aorta, which is the major artery which leaves the heart is also smaller than usual.

During the initial several days after birth, the work of pumping the blood to varied parts of the body as well as the lungs is performed by the right side of the body via the foramen ovale, i.e., a natural opening located between the two upper cardiac chambers, or via the ductus arteriosus, i.e., a blood vessel that directly joins the pulmonary artery to the aorta. When the ductus arteriosus and the foramen ovale are in an open state, then they are known as being “patent.”

The foramen ovale and the ductus arteriosus normally close a couple of days after birth. Thus the right side of the heart has no options to pump blood across the body. It may however be noted that individuals with hypoplastic left heart syndrome have another cardiac defect called atrial septal defect; it is a hole present between the atria, i.e., the upper cardiac chambers. This permits the right side of the heart to keep pumping blood across the body even after the closure of the foremen ovale and or the ductus arteriosus.

Treatment of hypoplastic left heart syndrome

Hypoplastic left heart syndrome can be corrected via a surgery or a heart transplant. In the meantime, the health care provider may suggest the below listed treatment options to manage the symptoms:

• Medications such as alprostadil to keep open the ductus arteriosus and dilate the different blood vessels.
• Administration of intravenous fluids via a tubed passed into a vein.
• Underlying breathing problems can be corrected via breathing assistance. The baby may be put on a ventilator to facilitate the supply of sufficient oxygen into the body.
• After closure of the foramen ovale, doctors may perform a procedure called atrial septostomy, wherein an opening is created between the two upper chambers of the heart. This procedure may not be necessary if atrial septal defect is already present.

Surgery

Surgical correction of hypoplastic left heart syndrome involves a three-step procedure which will facilitate the normal supply of blood in and out of the heart.

Step 1: It involves the Norwood operation wherein the aorta is reconstructed and connected directly the right ventricle, thereby allowing it to pump blood into both the body and the lungs.

Step 2: It involves a hemi-Fontan or bi-directional Glenn procedure, wherein most of the blood returning from the upper body flows directly into the lungs. This reduces the workload on the right ventricle. Also, more oxygen-rich blood is pumped via the aorta to supply to varied tissues and organs in the body.

Step 3: It involves the Fontan procedure, wherein the remainder of the blood flowing back from the body goes directly into the lungs. Thus there is no mixing of oxygen-poor and oxygen-rich blood in the heart, and the skin no longer has the bluish hue.

Hypoplastic left heart syndrome Life Expectancy

Most cases are diagnosed before birth. Children with this condition may appear healthy post birth but may develop breathlessness in due course. Statistics shows that close to 62 percent patient survive all of the three operations that are needed. Though there is not much concrete evidence, it has been observed that life expectancy of Hypoplastic left heart syndrome in case of the babies surviving all the three surgical procedures, is teenage.