Scimitar Syndrome - Causes, Signs and Symptoms, Diagnosis, and Treatment

Introduction:

Congenital heart defects affect the development of the heart, leading to structural abnormalities. Proper development of the heart is crucial in maintaining the body’s normal function. Structural defects in the heart can lead to several complications like heart failure, hypertension, respiratory and cardiac infections, abnormal heart rhythms, etc. These defects might occur independently or be associated with a syndrome. Down’s syndrome is the most common cause of congenital heart defects.

What Is Scimitar Syndrome?

Scimitar syndrome was first described by Catherine Neill, a British pediatric cardiologist, in 1960. It is a rare clinical condition characterized by an underdeveloped right lung, abnormal positioning of the heart, and abnormal blood drainage into the systemic circulation.

It is important to know the various parts involved to understand the condition better.

• The pulmonary artery is a blood vessel that carries impure blood from the right side of the heart to the lungs.

• The pulmonary vein is a blood vessel that carries pure blood from the lungs to the left side of the heart.

• The superior vena cava and inferior vena cava are the major blood vessels in the body that carry impure blood from all body parts into the right side of the heart.

• The atrium and ventricles are the upper and lower chambers of the heart, respectively.

In healthy individuals, the impure blood from the right side of the heart travels to the lungs for purification and the pure blood returns to the left side of the heart via the pulmonary vein.

What Happens in Scimitar Syndrome?

• There is partial or complete deviated blood drainage from the pulmonary vein to the inferior vena cava in Scimitar syndrome.

• The term Scimitar syndrome is derived from the curvilinear shadow created on the chest X-ray by the anomalous pulmonary vein.

Other Characteristics:

• Hypoplasia (immature or underdeveloped right lung).

• Underdeveloped pulmonary artery.

• Sometimes blood from the left side of the heart diverts back into the lungs instead of going into the systemic circulation.

What Is the Mechanism by Which a Healthy Heart Pumps Blood?

A properly functioning heart receives blood from the entire body and delivers it to the lungs. Blood takes up oxygen in the lungs and returns it to the heart and the remainder of the body.

The human body's circulatory system, a network of blood vessels, transports blood throughout it. Two different kinds of blood vessels carry blood:

• The body's arteries transport blood that is rich in oxygen from the heart to other areas.

• Blood with low oxygen content is returned to the heart by veins from other areas of the body.

What Causes Scimitar Syndrome?

The exact cause underlying the Scimitar syndrome is not yet identified. In addition, genetic mutations linked explicitly to Scimitar syndrome have not been reported so far.

How Commonly Does Scimitar Syndrome Occur?

It is a rare congenital heart condition that affects one to three infants per 1,00,000 live births. It affects females more than males at a ratio of 2:1. Around three to six percent of all partial anomalous pulmonary vein connections are diagnosed as Scimitar syndrome. Not all cases may be reported because many patients remain asymptomatic. Cases running in families are also described in many studies.

What Are the Signs and Symptoms of Scimitar Syndrome?

A majority of cases remain asymptomatic or show minor symptoms. If present, the symptoms include:

• Symptoms of heart failure are usually associated with other congenital heart conditions. These include shortness of breath, fatigue, swelling in the legs, irregular and rapid heartbeats, etc.

• Symptoms of recurrent pulmonary infection include cough, throwing up blood while coughing, pressure in the chest, difficulty breathing, fever, etc.

How Is Scimitar Syndrome Diagnosed?

Diagnosis is made by using advanced imaging and scanning techniques.

1. Plain Radiography:Plain radiography is a valuable aid in the diagnosis of congenital heart diseases. This is because it can detect structural defects in the heart based on physiology. However, there is always a risk of radiation exposure. The plain chest radiographs reveal a small, underdeveloped lung with an anomalous vein seen as a tube-like structure parallel to the right side of the heart in the shape of a Turkish sword (Scimitar).

2. CT (Computed Tomography): Computed tomography can produce high-quality three-dimensional images and detect the heart's structural defects accurately. Therefore, it has a supplementary role in diagnosing and differentiating between normal and pathologic features.

3. MRI (Magnetic Resonance Imaging):MRI is used to evaluate the structure of the heart, its chambers, valves, blood vessels, and surrounding structures. It also detects an abnormality in the blood flow patterns, and hence it is helpful to detect Scimitar syndrome.

4. Echocardiography:It is a commonly used tool in pediatric cases as it is non-invasive. It provides information regarding the structural abnormalities as well as the position of the heart and blood vessels.

5. Angiography:A special three-dimensional angiography utilizes rotational volumetric imaging for enhanced spatial visualization of complex cardiac structures.

How Is Scimitar Syndrome Treated?

If patients are symptomatic, surgery is the treatment of choice. Correction of the abnormality should be done if there is a significant connection between the right and left chambers of the heart. A tunnel or baffle is created in the blood vessels to redirect blood flow. Alternatively, the abnormally positioned vein can be reimplanted in the right place.

What Are the Risks Associated With Scimitar Syndrome?

The persistent presence of a connection between the right and left chambers can lead to pulmonary hypertension (a type of blood pressure that affects the right side of the heart and lungs). The Eisenmenger phenomenon is another complication that develops due to unrepaired congenital defects of the heart.

Which Illnesses Have a Connection to Scimitar Syndrome?

Numerous Scimitar syndrome sufferers also struggle with other cardiovascular issues. Alternatively, Scimitar syndrome could result in more issues.

Other heart issues that people may have include:

• ASDs, or atrial septal defects, are holes between the heart's two upper chambers.

• Horseshoe lungs occur When two portions of the lungs join abnormally.

• The accessory lung, also known as pulmonary sequestration, is a segment of detached lung tissue that has an irregular blood supply or no function.

• An opening between the two heart-pumping chambers is known as a ventricular septal defect.

How Can the Likelihood of Having a Child With Scimitar Syndrome Be Decreased?

It is impossible to prevent a youngster from developing Scimitar syndrome. The likelihood of giving birth to a healthy child can be raised by:

• Avoiding dangerous substances when pregnant, such as nicotine, alcohol, and recreational drugs.

• Weighing the advantages and disadvantages of any drug with a physician.

• Get vaccinated against rubella since an infection might harm the baby's heart development.

• Taking care of long-term illnesses like diabetes.

• Taking prenatal vitamins, including Folic acid, as prescribed.

What Is the Prognosis for Individuals With Scimitar Syndrome?

Scimitar syndrome patients who undergo surgery usually experience excellent long-term results. After surgery, the majority of patients no longer have Scimitar syndrome symptoms. Some individuals, particularly infants and young toddlers, may experience some constriction of the pulmonary vein that has been redirected, necessitating further care.

Conclusion:

Scimitar syndrome is a condition characterized by a small right lung, abnormal position of the heart, and abnormal blood drainage into the systemic circulation. It affects one to three infants per 1,00,000 live births. It affects females more than males at a ratio of 2:1. A majority of cases remain asymptomatic or show minor symptoms. If present, the symptoms include shortness of breath, fatigue, swelling in the legs, irregular and rapid heartbeats, etc. Diagnosis is made by using advanced imaging and scanning techniques, and if patients are symptomatic, surgery is the treatment of choice.