Chapter 26

 

EBSTEIN ANOMALY

    This is a relatively common situation which consists of a complex defect at the level of the tricuspid valve. Contrary to the opinion of many others, the implantation of the tricuspid valve seems to be normal in patients with Ebstein's anomaly, but the posterior and medial leaflet of the tricuspid valve is abnormally adherent to the ventricular wall. Since this leaflet is larger than normal, it gives rise to the impression of an abnormally low implantation of the tricuspid valve. As a consequence, the right atrium is much larger than normal and part of the right atrial wall will be actually the remainder of the right ventricular wall located over the tricuspid valve.
    The right ventricle is abnormally small.
    Tricuspid regurgitation and pulmonary valve stenosis may be observed in combination with Ebstein's anomaly. The foramen ovale is patent in most of these patients and a bidirectional or right to left shunt may be observed. In rare cases of complete transposition of the great arteries, the findings of Ebstein's anomaly can be noted on the left side of the heart.

CLINICAL PICTURES

    There is frequent history of moderate cyanosis after birth.
    Most of these patients (70 to 80%) are not necessarily cyanotic during infancy but will turn cyanotic during adolescence.
    The cyanosis is in general moderate and depends upon the percentage of oxygen saturation of the aterial level which usually varies between 50 and 98%. Many times cyanosis may be related to physical exertion and even to pulmonary embolism.
    The clinical picture will relate to three different circumstances:

  1. Degree of shunting
  2. Cardiac failure
  3. Arrhythmia

    A large percentage of these patients will present symptoms of some degree of congestive failure during infancy.
    Arrhythmias, Wolff-Parkinson-White syndrome, paroxysmal atrial tachycardia, based on re-entry mechanisms, etc. may often constitute the main complaint of these patients.
    Cerebral embolism due to right to left shunt was described many times.
    The most prevalent physical findings are mild to significant jugular venous distension and hepatomegaly, in relation to the hemodynamic condition of the patient.
    Distant cardiac sounds are almost the rule with wide splitting of the second sound.
    Tricuspid insufficiency with its typical jugular venous pulse and murmur, may also appear in most of these patients. Hepatic pulsation can also occur. If ventricular septal defect, atrial septal defect or pulmonary stenosis are present, the physical findings will vary in relation to such malformations.
    The main hemodynamic feature of Ebstein's is due to the small and ineffective right ventricular activity. The most striking physical finding is the poor cardiac impulse in relation to the patient's marked cardiomegaly.
    Finally, with a pace which is rather particular for each patient, extreme cardiomegaly and marked cyanosis develop. In any event, surprising survival is achieved many times in spite of striking cardiac hypertrophy and marked cyanosis.

ELECTROCARDIOGRAM

  1. The electrocardiogram is typical with the association of complete right bundle branch block with extremely short R and S waves in the precordial leads. This is quite a typical pattern in congenital heart disease which correlates with the majority of patients with Ebstein's anomaly. A small QRS complex with complete right bundle branch block in the right precordial leads may have multiphasic spikes with at times initial Q wave and always a short R wave with inverted T in lead V1 and V2.
  2. P pulmonale will be present in the majority of cases with inverted P wave in lead V1.
  3. In a large number of cases of Ebstein's anomaly, Wolff-Parkinson-White syndrome (pre-excitation syndrome) will be present. The most frequent type is Type B which resembles left bundle branch block.
  4. In other patients, prolongation of the PR interval was reported. In Ebstein's anomaly, crises of paroxysmal atrial tachycardia frequently simulates ventricular tachycardia.
  5. Normal electrocardiogram, however, is not unusual.

ROENTGENOGRAM

    The chest x-ray usually shows a marked globulose cardiomegaly with significant right atrial enlargement. If pulmonary stenosis and right to left shunt is present, the lung blood flow will be diminished. The cardiac dynamic is feeble at fluoroscopic examination.

SUMMARY

    The clinical, electrocardiographic and roentgenogram picture of these patients is rather typical, allowing clinical diagnosis in most of cases. In fact, the association of the following findings is highly presumptive of Ebstein's anomaly:

  1. Patient with history of moderate, intermittent and progressive cyanosis
  2. History of episode of paroxysmal atrial tachycardia
  3. Murmur and jugular pulse of tricuspid insufficiency
  4. Electrocardiogram showing sinus rhythm with giant P waves and low voltage QRS complex with right bundle branch block
  5. Marked cardiomegaly, in many cases of the gobular type
  6. Findings of Wolff-Parkinson-White syndrome in the electrocardiogram

ECHOCARDIOGRAM IN EPSTEIN ANOMALY AND TRICUSPID VALVE EVALUATION

    Leftward deviation of the tricuspid valve is described and many times as a direct consequence, both mitral and tricuspid valve can be simultaneously visualized sonographically. Abnormal delay in the tricuspid valve closure was also described, which occurs more than 50 milliseconds after the mitral valve. Both signs are usually not reliable enough to have significant value in the final diagnosis of this disease.
    The frequent associated malformations noted with Ebstein's anomaly makes the final role of ultrasound in this disease of not too much of a value.
    The "four chamber view" or also called "apex view" on real time echo, is particularly helpful in this entity.

CATHETERIZATION

    Catheterization can confirm the diagnosis with a simultaneous recording of pressures in the right atrium with an intracavitary electrocardiogram The associated malformations (atrial septal defect, pulmonary stenosis, etc.) are also to be evaluated during the catheterization.

ANGIOGRAPHIC STUDY

    Angiographic study will show the typical displacement of the tricuspid valvular level. Many times a differential diagnosis is to be done with tricuspid atresia, infundibular pulmqnary stenosis and pulmonary valve stenosis, atrial septal defect and endocardiac fibroelastosis and aplasia of the myocardium of the right ventricle (UHLS anomaly).
    Cardiac catheterization and angiographic studies carry a higher risk than normal in these patients, due to frequent arrhythmias.

MEDICAL AND SURGICAL TREATMENT

    Medical treatment will consist of the treatment of the congestive heart failure, arrhythmias and prevention of bacterial endocarditis.
    Surgery attempts the reconstruction of the tricsupid valve or prosthetic replacement.


Diagram of Ebstein malformform depicting the main features in its anatomy and pattern of circulation. Many times Ebstein malformation is associated with gross incompetence of the tricuspid valve and infundibular stenosis at the outflow tract of the right ventricle. Pulmonary valve atresia is not unusuaL


Pulmonary valve atresia and Ebstein anomaly. As a consequence of the tricuspid valve formation the right ventricle may eventually enlarge considerably.


Electrocardiogram of a 22 year-old patient with Ebstein Anomaly. The trace shows Atrial Fibrillation with high ventricular response in a patient with Wolf-Parkinson- White Syndrome. Atrial Fibrillation in WPW Syndrome can be frequently mistaken for ventricular tachycardia or even ventricular fibrillation due to the ventricular aberrancy and the reputation of irregularity of ventricular tachycardia.
WPW Syndrome is a common finding in patients with Ebstein Malformation.