Ebstein anomaly is a rare congenital heart disorder in which parts of the tricuspid valve are abnormal. The tricuspid valve (or the atrioventricular valve) is the valve between the right atrium (upper chamber) and right ventricle (lower chamber) of the heart. Normally, the tricuspid valve is made of three flaps. These flaps open to allow blood flow from the right atrium (upper chamber) to the right ventricle (lower chamber) when the heart relaxes. They close to prevent the backflow of blood back to the right atrium from the right ventricle while the heart pumps.
In people with the Ebstein anomaly, the flaps are too large and are placed too deep in the right ventricle. The valve works poorly and blood goes the wrong way. A domino effect occurs where the backup of blood flow leads to heart enlargement, fluid buildup and narrowing of the pulmonary valve (valve which leads to the lungs). This defect can also lead to an atrial septal defect which is a hole in the wall separating the heart’s two upper chambers. This results in oxygen-deficient blood going to the rest of the body hence causing cyanosis which is a blue tint to the skin like the lips or ears caused by oxygen-poor blood.
About one in 20,000 infants are born with Ebstein anomaly and it accounts for less than 1 per cent of all congenital heart defects, so, fortunately, it is rare. However, mild forms of Ebstein anomaly might not cause symptoms, until later in adulthood. Symptoms include shortness of breath, fatigue, heart palpitations or arrhythmias (abnormal heart rhythms).
A short view back to the past
This term was coined from the name, Dr Wilhelm Ebstein. On 28 June 1864, Dr Ebstein's hospital admitted Joseph Prescher, a 19-year old labourer, whose childhood dyspnea (shortness of breath) and palpitations had worsened with age. A clinical study presented a congenital heart defect. Eight days later, the patient died and Dr Ebstein performed the autopsy. He then published a case report, 'a very rare case of tricuspid regurgitation caused by a congenital defect.’ He described the anatomy and clinical findings with precision and grace in the case study. He presented connections, unique observations and important details concluding that this case was unique. The rarity and the contribution of the doctor, in this case, give this disorder the term, ‘Ebstein Anomaly.’
So what are the causes, what is the root of the problem?
This is where the term ‘anomaly’ comes into play.
The cause is unknown. ‘However, there are theories. There are heterogeneous genetic factors. Studies suggest genetic, reproductive and environmental factors. For example, this anomaly is more common in twins, in those with a family history of congenital heart disease and in those with maternal exposure to benzodiazepines (a class of psychoactive drugs that are depressants, usually prescribed for anxiety or insomnia) or lithium. Most cases are sporadic though, familial Ebstein’s anomaly is rare.
Diagnosis and Treatment
A variety of diagnostics tests are done to determine the cause.
An Echocardiogram: it uses sound waves to produce detailed images of the heart showing the structure of the tricuspid valve.
A Holter monitor: This device is portable and records your heart’s electrical activity as you perform normal activities for a day or two.
A chest X-ray: a picture of your heart, lungs and blood vessels that can show heart enlargement.
Pulse oximetry: a sense attached to your finger or toe measures the amount of oxygen in your blood.
Exercise Stress test: your blood pressure, heart rate, heart rhythm and breathing are all monitored as you walk on a treadmill or ride a stationary bike. Shows how your heart responds to exercise and what level of physical activity is safe.
To treat, there are surgical and therapeutic options depending on the severity of the case.
Patients are treated with standard heart failure therapy including diuretics and digoxin. Surgical options include the replacement of the tricuspid valve using various methods to increase the success rate.
One other method is the use of the ‘Bioglis’ valve in surgical treatment. This valve was formed using a flexible frame, from the hepatic Glisson’s capsule (capsule of the liver) of bull calves. Twelve consecutive patients underwent surgery and their results were analysed. The results showed good function and there were no in-hospital deaths or complications. Such innovative studies and ideas pave the path for a definite cure for this disorder.
The Case Study that gave rise to the discussion:
This case study includes details of his findings and observations. It gives an insight to his thought process!
‘He considered the tricuspid anomaly to be the most important feature. In a thorough and beautiful fashion, Ebstein described how the proximal anterior leaflet partially blended with the ventricular endocardium and how the remainder of the anterior leaflet was tethered by multiple chordae to the ventricular endocardium.’
‘The excellent correlation of Ebstein’s pathologic findings with Kornfeld’s clinical notes and his hypothesis of the pathophysiology of Ebstein’s anomaly make his publication a landmark in the description of a new entity. In addition, it provided a strong basis for the development of repair techniques for this rare anomaly 100 years later.’
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Written by: Svasti Tewari
Edited by: Sakshi Deshpande
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