Ebstein's anomaly is a
congenital heart defect
A congenital heart defect (CHD), also known as a congenital heart anomaly and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital heart defect is classed as a cardiovascular ...
in which the septal and posterior leaflets of the
tricuspid valve
The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, at the superior portion of the right ventricle. The function of the valve is to allow blood to flow from the right atrium to the right vent ...
are displaced towards the apex of the
right ventricle
A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the upper ...
of the
heart
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...
.
It is classified as a critical
congenital heart defect
A congenital heart defect (CHD), also known as a congenital heart anomaly and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital heart defect is classed as a cardiovascular ...
accounting for less than 1% of all congenital heart defects presenting in around per 200,000 live births. Ebstein anomaly is the congenital heart lesion most commonly associated with
supraventricular tachycardia
Supraventricular tachycardia (SVT) is an umbrella term for fast heart rhythms arising from the upper part of the heart. This is in contrast to the other group of fast heart rhythms – ventricular tachycardia, which start within the lower cham ...
.
Signs and symptoms
The annulus of the valve is still in the normal position. The valve leaflets, however, are to a varying degree, attached to the walls and septum of the right ventricle. A subsequent "atrialization" of a portion of the morphologic right ventricle (which is then contiguous with the right atrium) is seen. This causes the right atrium to be large and the anatomic right ventricle to be small in size.
*
S3 heart sound
*
S4 heart sound
* Triple or quadruple gallop due to widely split S1 and S2 sounds plus a loud S3 and/or S4
* Systolic murmur of
tricuspid regurgitation
Tricuspid regurgitation (TR), also called tricuspid insufficiency, is a type of valvular heart disease in which the tricuspid valve of the heart, located between the right atrium and right ventricle, does not close completely when the right ventri ...
= Holosystolic or early systolic murmur along the lower left sternal border depending on the severity of the regurgitation
* Right atrial hypertrophy
* Right ventricular conduction defects
*
Wolff-Parkinson-White syndrome often accompanies
Related abnormalities
While Ebstein's anomaly is defined as the congenital displacement of the tricuspid valve towards the apex of the right ventricle, it is often associated with other abnormalities.
Anatomic abnormalities
Typically, anatomic abnormalities of the tricuspid valve exist, with enlargement of the anterior leaflet of the valve. The other leaflets are described as being plastered to the endocardium.
Tethering the underlying ventricular wall is the most common for the posterior and septal leaflets, and sail-like anterior leaflets may be tethered to the RV free wall also.
![ECGs in Ebstein's anomoly with Mahaim accessory pathway](https://upload.wikimedia.org/wikipedia/commons/3/32/ECGs_in_Ebstein%27s_anomoly_with_Mahaim_accessory_pathway.png)
About 50% of individuals with Ebstein's anomaly have an associated shunt between the right and left atria, either an
atrial septal defect
Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this d ...
or a
patent foramen ovale
Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this d ...
.
Electrophysiologic abnormalities
About 50% of individuals with Ebstein's anomaly have an
accessory pathway An accessory pathway is an additional electrical connection between two parts of the heart. These pathways can lead to abnormal heart rhythms or arrhythmias associated with symptoms of palpitations. Some pathways may activate a region of ventricula ...
with evidence of Wolff-Parkinson-White syndrome, secondary to the atrialized right ventricular tissue. This can lead to abnormal heart rhythms including
atrioventricular re-entrant tachycardia.
Other abnormalities that can be seen on the ECG include:
# signs of right atrial enlargement or tall and broad 'Himalayan' P waves
#
first degree atrioventricular block
First-degree atrioventricular block (AV block) is a disease of the electrical conduction system of the heart in which electrical impulses conduct from the cardiac atrium (heart), atria to the ventricle (heart), ventricles through the atrioventricul ...
manifesting as a prolonged PR-interval
# low amplitude QRS complexes in the right precordial leads
# atypical
right bundle branch block
A right bundle branch block (RBBB) is a heart block in the right bundle branch of the electrical conduction system.
During a right bundle branch block, the right ventricle is not directly activated by impulses travelling through the right bu ...
# T wave inversion in V1-V4 and Q waves in V1-V4 and II, III and aVF.
Risk factors
An enlargement of the
aorta
The aorta ( ) is the main and largest artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries). The aorta distributes ...
may occur; an increased risk of abnormality is seen in babies of women taking
lithium
Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid el ...
during the first trimester of pregnancy
(though some have questioned this)
and in those with
Wolff-Parkinson-White syndrome.
Diagnosis
An echocardiogram is the most common and specific way to diagnose Ebstein’s anomaly because it effectively shows all 4 chambers of the heart, which displays the distance between the hinge point of the septal leaflet of the tricuspid valve and the anterior leaflet of the mitral valved (displacement index) to determine if the value is greater than 8mm/m
2.
Treatment
Medication
Ebstein's cardio physiology typically presents as an (antidromic) AV reentrant tachycardia with associated
pre-excitation
Pre-excitation syndrome is a heart condition in which part of the cardiac ventricles are activated too early. Pre-excitation is caused by an abnormal electrical connection or accessory pathway between or within the cardiac chambers. Pre-excitatio ...
. In this setting, the preferred medication treatment agent is
procainamide
Procainamide (PCA) is a medication of the antiarrhythmic class used for the treatment of cardiac arrhythmias. It is classified by the Vaughan Williams classification system as class Ia; thus it is a sodium channel blocker of cardiomyocytes. In add ...
. Since AV-blockade may promote conduction over the accessory pathway, drugs such as
beta blockers
Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage cardiac arrhythmia, abnormal heart rhythms, and to protect the heart from a second myocardial infarction, heart attack after a first heart ...
,
calcium channel blocker
Calcium channel blockers (CCB), calcium channel antagonists or calcium antagonists are a group of medications that disrupt the movement of calcium () through calcium channels. Calcium channel blockers are used as antihypertensive drugs, i.e., as ...
s, and
digoxin
Digoxin (better known as Digitalis), sold under the brand name Lanoxin among others, is a medication used to treat various heart conditions. Most frequently it is used for atrial fibrillation, atrial flutter, and heart failure. Digoxin is on ...
are contraindicated.
If
atrial fibrillation with pre-excitation occurs, treatment options include procainamide,
flecainide
Flecainide is a medication used to prevent and treat abnormally fast heart rates. This includes ventricular and supraventricular tachycardias. Its use is only recommended in those with dangerous arrhythmias or when significant symptoms cannot ...
,
propafenone
Propafenone, sold under the brand name Rythmol among others, is a class 1c anti-arrhythmic medication, which is used to treat illnesses associated with rapid heart beat such as atrial and ventricular arrhythmias.
Mechanism of action
Propafen ...
,
dofetilide
Dofetilide is a class III antiarrhythmic agent. It is marketed under the trade name Tikosyn by Pfizer, and is available in the United States in capsules containing 125, 250, and 500 µg of dofetilide. It is not available in Europe or Australia. I ...
, and
ibutilide
Ibutilide is a Class III antiarrhythmic agent that is indicated for acute cardioconversion of atrial fibrillation and atrial flutter of a recent onset to sinus rhythm. It exerts its antiarrhythmic effect by induction of slow inward sodium current ...
, since these medications slow conduction in the accessory pathway causing the tachycardia and should be administered before considering electrical
cardioversion
Cardioversion is a medical procedure by which an abnormally fast heart rate (tachycardia) or other cardiac arrhythmia is converted to a sinus rhythm, normal rhythm using electricity or pharmaceutical drug, drugs. Synchronized electrical cardiover ...
. Intravenous
amiodarone
Amiodarone is an antiarrhythmic medication used to treat and prevent a number of types of cardiac dysrhythmias. This includes ventricular tachycardia (VT), ventricular fibrillation (VF), and wide complex tachycardia, as well as atrial fibrilla ...
may also convert atrial fibrillation and/or slow the ventricular response.
Surgery
The
Canadian Cardiovascular Society
The Canadian Cardiovascular Society (CCS) is the national voice for cardiovascular physicians and scientists in Canada. The CCS is a membership organization that represents more than 1,800 professionals in the cardiovascular field. Its mission is ...
(CCS) recommends surgical intervention for these indications:
* Limited exercise capacity (
NYHA III-IV)
* Increasing heart size (cardiothoracic ratio greater than 65%)
* Important
cyanosis
Cyanosis is the change of body tissue color to a bluish-purple hue as a result of having decreased amounts of oxygen bound to the hemoglobin in the red blood cells of the capillary bed. Body tissues that show cyanosis are usually in locations ...
(resting
oxygen saturation
Oxygen saturation (symbol SO2) is a relative measure of the concentration of oxygen that is dissolved or carried in a given medium as a proportion of the maximal concentration that can be dissolved in that medium at the given temperature. It ca ...
less than 90% - level B)
* Severe
tricuspid regurgitation
Tricuspid regurgitation (TR), also called tricuspid insufficiency, is a type of valvular heart disease in which the tricuspid valve of the heart, located between the right atrium and right ventricle, does not close completely when the right ventri ...
with symptoms
*
Transient ischemic attack
A transient ischemic attack (TIA), commonly known as a mini-stroke, is a minor stroke whose noticeable symptoms usually end in less than an hour. TIA causes the same Symptoms of stroke, symptoms associated with strokes, such as weakness or numbn ...
or
stroke
A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...
The CCS further recommends patients who require operation for Ebstein's anomaly should be operated on by congenital heart surgeons who have substantial specific experience and success with this operation. Every effort should be made to preserve the native tricuspid valve.
History
Ebstein's anomaly was named after
Wilhelm Ebstein
Wilhelm Ebstein (27 November 1836, Jawor, Jauer, Prussian Silesia – 22 October 1912) was a German physician. He proposed a Low-carbohydrate diet, low-carbohydrate high-fat diet to treat obesity. Ebstein's anomaly is named for him.
Biography
...
, who in 1866 described the heart of the 19-year-old patient Joseph Prescher. Joseph Prescher was cyanotic with dyspnea, palpitations, jugular venous distension, and cardiomegaly. At autopsy, “Ebstein described an enlarged and fenestrated anterior leaflet of the tricuspid valve.” In addition, “the posterior and septal leaflets were hypoplastic, thickened, and adherent to the right ventricle. There was also a thinned and dilated atrialized portion of the right ventricle, an enlarged right atrium, and a patent foramen ovale.”
[Attenhofer Jost, C. H., Connolly, H. M., Dearani, J. A., Edwards, W. D., & Danielson, G. K. (2007). Ebstein’s anomaly. Circulation, 115(2), 277–285. https://doi.org/10.1161/circulationaha.106.619338]
References
External links
{{Congenital malformations and deformations of circulatory system
Congenital heart defects