EBSTEIN ANOMALY: A COMPLEX HEART DEFECT
Medically Reviewed by Dr. Rae Osborn, Ph.D., June 13, 2024
Ebstein Anomaly is a rare congenital heart defect that affects the tricuspid valve, which divides the right atrium (upper chamber) and the right ventricle (lower chamber) of the heart[1].
This condition is characterized by a malformed tricuspid valve, specifically the anterior leaflet that does not function properly, causing constant tricuspid valve regurgitation characterized by the abnormal backflow of blood from the right ventricle to the right atrium [2]. The right atrium is smaller than the right ventricle under normal circumstances. Yet if valve regurgitation is severe enough, the right atrium can swell and become larger than the right ventricle, leading to heart enlargement.
More than half of patients with Ebstein Anomaly also have a patent foramen ovale[3]. This is an atrial septal defect in which there is an opening in the muscle wall between the right and left atrium. This defect is common in those with Ebstein Anomaly and can potentially lead to cyanosis, a condition characterized by a bluish discoloration of the skin.
In severe cases, the right ventricle might not be strong enough to push blood through the lungs, causing functional pulmonary atresia.
What Causes the Ebstein Anomaly?
Ebstein anomaly is a rare heart defect, comprising less than 1% of all congenital heart issues. It happens in less than 1 in every 10,000 live births. While some instances are familial and inherited, most cases are spontaneous with no known cause. Etiology of the condition may be multifactorial, potentially involving environmental exposures and genetic predisposition.
Some studies have shown a possible link between the use of certain medications during pregnancy and the development of Ebstein's Anomaly in the baby.
Studies have linked the anomaly with several gene mutations, including[4]:
- Duplications in chromosome 15q.
- Rearrangements in chromosome 11q.
- Mutations in the MYH7 gene are associated with cardiomyopathies.
- Mutations in the NKX2-5 gene, a cardiac transcription factor that links atrial septal defects and atrioventricular conduction defects.
Those with Ebstein’s anomaly due to mutations of the MYH7 gene stand a 50% chance of passing the condition on to their children[5]. The MYH7 gene mutation is inherited as an autosomal dominant trait. Women are 10 times more likely than men to pass the condition on to their offspring.
Risk Factors
While the exact cause of Ebstein Anomaly is unknown, some risk factors may increase the likelihood of a baby being born with this condition. These include:
- Family history of congenital heart defects
- Exposure to certain medications during pregnancy
- Maternal exposure to second-hand smoking during pregnancy
- Maternal and paternal age over 40
- Alcohol or illicit drug intake during pregnancy
- Premature birth
Various other heart conditions are associated with Ebstein anomaly and may increase the risk[6]:
- 80% of those with Ebstein anomaly also have an atrial septal defect dividing the two upper chambers.
- 5-25% of patients have Wolff Parkinson White Syndrome, which is a heart condition in which a secondary electrical pathway gives rise to episodic arrhythmia.
The following factors may exacerbate the severity of symptoms seen in those with Ebstein anomaly:
- Hypertension (high blood pressure), especially in the lungs (pulmonary hypertension)
- Heart infections
- Radiation to the chest area
- Pacemaker use
Signs And Symptoms: When to See a Doctor
In many cases, there are no symptoms, and a diagnosis is reached when assessing for other conditions. Symptoms tend to occur in moderate to severe cases.
In those with symptoms, their severity varies considerably. Some may acquire mild symptoms from the condition, while others may have severe ones requiring immediate medical attention.
Some common signs and symptoms of Ebstein Anomaly include:
- Bluish tinge to the skin, lips, or nails
- Difficulty breathing or shortness of breath
- Fatigue
- Poor appetite
- Swelling in the legs or abdomen
- Rapid or irregular heart rate
- Dizziness or fainting
- Chest pain
If you or your child experiences symptoms of Ebstein Anomaly, it is essential to see a specialist for a proper evaluation and treatment plan.
Potential Complications
Ebstein Anomaly can lead to a variety of complications, including:
- Trouble breathing
- Congestive heart failure
- Abnormal heart rhythms and Atrial fibrillation
- Cyanosis (bluish color) due to low oxygen levels in the blood
- Stroke
- Heart valve infections
- Heart enlargement
- Heart failure
- Sudden cardiac death
A patient with untreated Ebstein anomaly can suffer a wide variety of blood flow-related problems that result in multi-organ congestion involving dysfunction of the heart, lungs, liver, spleen, and kidneys. These problems tend to emerge decades after living with the issue and can considerably shorten patients' lifespans.
Pregnancy and Ebstein Anomaly
Pregnancy can be a high-risk situation for women with Ebstein Anomaly. The changes in the body during pregnancy can put added strain on the heart, which can lead to complications. Women with Ebstein Anomaly need to work closely with their doctors to monitor their heart health during pregnancy.
How is Ebstein Anomaly Diagnosed?
A diagnosis of Ebstein Anomaly typically occurs during pregnancy or shortly after birth. A fetal echocardiogram, a type of ultrasound, can detect the condition during pregnancy.
After birth, a cardiologist may suspect the condition from a heart murmur during a physical exam in which they listen to the patient's heartbeat. The location and sound of the murmur can give a clue as to the diagnosis.[7]
A cardiologist will then run a series of tests to confirm the diagnosis. These can include any of the following:
- Chest X-ray
- Electrocardiogram
- Echocardiogram
- Cardiac MRI
- Cardiac catheterization
Treatment Options for Ebstein Anomaly
While living with Ebstein Anomaly can present challenges, it is possible to live an active life with proper management and treatment.
The treatment for Ebstein Anomaly depends on the severity of the tricuspid regurgitation and the symptoms experienced by the individual. In some instances, treatment is not necessary, and the condition only requires close monitoring.
If symptoms are present, surgery is often necessary to correct the defect. If left untreated, those with Ebstein anomaly may live to an average of 32 years old, whereas with surgical repair, they can live an average lifespan.[8]
Medications can assist with managing symptoms and improving heart function until surgery takes place. This benefits infants until they are old enough to receive surgery or older patients on a waiting list.
Numerous surgeries can repair Ebstein's Anomaly. Some of the main procedures include:
Cone reconstruction surgery is an open heart surgery that involves reshaping the tricuspid valve to improve its function and reduce regurgitation, resulting in better long-term outcomes and improved heart function for those with Ebstein anomaly.[9]
Catheter ablation is a minimally invasive surgical method that uses a catheter to target and destroy abnormal heart tissue responsible for causing abnormal heart rhythms[10] (caused by an accessory pathway such as occurs with WPWS). Accessory pathways, in general, occur in about 5% to 25% of people who have Ebstein anomaly. During a catheter ablation procedure, a thin, flexible tube (catheter) is guided through blood vessels to the heart, delivering targeted energy (such as radiofrequency or cryotherapy) to destroy or modify the abnormal heart tissue, restoring normal heart rhythm.
Transcatheter procedures are minimally invasive techniques involving using a catheter to treat and repair heart valve abnormalities without needing open-heart surgery[11]. A few types of transcatheter procedures used to treat Ebstein anomaly include:
- Transcatheter tricuspid valve replacement: This involves replacing the tricuspid valve using a catheter, without open-heart surgery, to improve blood flow and reduce symptoms.
- Transcatheter tricuspid valve repair: This is a minimally invasive procedure that uses a catheter to correct abnormalities in the tricuspid valve, restoring its function and reducing regurgitation.
- Transcatheter tricuspid balloon valvuloplasty: In this procedure, a balloon is inserted into the tricuspid valve and inflated to widen the valve opening, relieving tricuspid stenosis and improving blood flow.
Heart transplantation can treat severe cases where repair is not possible.
The prognosis for most cases of surgery is generally positive.
Open heart surgery is preferable in complicated situations where heart surgeons require a better view of the heart tissue. The success rates of such surgery vary and are lower compared to less invasive transcatheter procedures. Transcatheter procedures have a high success rate[12] yet may not be suitable for complex cases with multiple congenital deformities. The accuracy and scope of these procedures are improving every year.
All surgical procedures risk bleeding, infection, and complications related to anesthesia. The risks are much lower with transcatheter techniques.
Individuals with Ebstein anomaly need to work closely with their doctors to monitor their heart health and manage any symptoms that may arise, even after surgery.
Latest Technology and Advancements
Advances in medical imaging and personalized medicine are revolutionizing Ebstein Anomaly treatment.
Some of the latest technology and advancements include:
3D Printing and Personalized Medicine: Incorporating 3D printing and personalized medicine into the treatment of Ebstein Anomaly allows for a tailor-made approach based on individual genetics and anatomy. By creating 3D models of the patient's heart[13], doctors can plan and optimize surgical interventions precisely, leading to more customized and effective treatment strategies.
Cardiac Regenerative Therapies: New insights into heart tissue regeneration are paving the way for developing new therapies that can enhance the heart's ability to heal[14]. Researchers are looking at stem cells to repair heart tissue[15] and self-regenerate heart valves to improve surgical procedures[16].
Gene Therapy: The future of treating Ebstein Anomaly may involve cardiac gene therapy[17], offering the potential for tissue repair and valve regeneration. These innovative approaches address the condition's underlying causes at a molecular level, potentially restoring heart function and structure for better long-term outcomes.
Improved Imaging Technology: Advances in imaging technology have transformed Ebstein Anomaly diagnostics and monitoring, offering clearer and more comprehensive views of the heart. High-resolution imaging techniques such as 3D echocardiography and cardiac magnetic resonance imaging (MRI)[18] enable healthcare professionals to visualize the heart's structure and function with unprecedented clarity, aiding in accurate diagnosis and treatment planning.
By leveraging these state-of-the-art technologies and advancements, healthcare providers can offer more personalized, effective, and innovative treatment options for individuals with Ebstein Anomaly, ultimately improving patient outcomes and quality of life.
Conclusion
Ebstein Anomaly is a complex heart defect that requires proper management and treatment. With advancements in technology and personalized medicine, individuals with this condition can lead complete and active lives. It is important to work closely with a doctor to monitor heart health and manage any symptoms that may arise. Individuals with Ebstein Anomaly can lead healthy and fulfilling lives with proper care.
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