Uhl Anomaly

A congenital disease characterized by the absence of a normal development of the myocardial layer of the right ventricle (usually replaced by fibrous or fatty tissue). Because the myocardial layer is dysplastic, the endocardium and epicardium are in apposition, which results in severe dilatation and early congestive cardiac failure. Chest radiography demonstrates marked cardiomegaly and right-sided chamber enlargement. Echocardiography and right-ventricle angiography demonstrate increased right heart volumes, severe diffuse hypokinesis, and tricuspid valve regurgitation.

Parchment Right Ventricle.

Congenital disorder first described by H.S. Uhl in 1952.

Very rare; 80 cases described in the literature.

It is inherited as autosomal dominant with reduced penetrance. Generally sporadic cases caused by mutations or the results of exposure to toxic or infective agents.

Not precisely known; may be the result of primary nondevelopment of myocytes or may be a result of selective apoptosis.

The diagnosis of right ventricular cardiomyopathy is based on the echocardiographic and angiographic documentation of localized or widespread structural and dynamic abnormalities involving mainly or exclusively the right ventricle. The absence of valvular disease, intracardiac shunts, active myocarditis, and/or coronary disease is essential to establish the diagnosis. The performance of endomyocardial biopsy is considered very useful in the differential diagnosis. The prognosis varies greatly from being lethal in the neonatal period to long-term survival in other individuals.

The major clinical feature is the presentation of different types of arrhythmias with a left bundle branch block pattern. The most important electrocardiographic abnormalities are T-wave inversion in the right precordial leads and the presence of late potentials in signal averaging ECG. The association with cardiac failure is rare except for those affected with the cardiomegalic form. There is a risk of sudden death and syncopal attacks due to ventricular fibrillation; however, most of the time the arrhythmias are well tolerated. Affected individuals often have good exercise tolerance and do not have a history of previous myocarditis. Congestive cardiac failure is the main sign; it may be associated with massive peripheral edema or massive pleural effusion leading to cardiac tamponade. Pulmonary atresia can be associated.

Evaluate the cardiac function (clinical, ECG, echocardiography, chest radiographs), and the extent of the pulmonary involvement (clinical, radiographs, arterial blood gas analysis). Also assess the hepatic function (clinical, laboratory investigation including coagulation test, ultrasound) because of the potential hepatic disturbance secondary to cardiac congestion.

Elective surgical procedures must be postponed until the cardiovascular function has been corrected. Patients presenting with congestive heart failure should not receive anesthesia for nonurgent procedures. The presence of pericardial and/or pleural effusions should be treated before the administration of anesthesia. Anesthetic agents should be primarily chosen on the basis of their effects on the pulmonary resistance (e.g., nitrous oxide, ketamine, etc.). The pulmonary vascular resistance should be maintained at the lowest possible level. Hypercarbia and hypoxemia should be avoided. Perioperative invasive cardiac monitoring is highly recommended.

Prophylactic antibiotics must be given as indicated. Nitrous oxide should be used with caution because of the effect on the pulmonary vascular resistance.

Ebstein Syndrome: This is a congenital heart defect characterized by displacement of the annulus of the tricuspid valve within the right ventricle (toward the apex of the ventricle) preventing the normal function of the right ventricle. This anomaly leads to loss of some right ventricle muscle mass, which is replaced by fibrous material, affecting contractility. Often associated with the destruction of the bundle of Kent, causing a condition called Wolff-Parkinson-White syndrome.

Arrhythmogenic Right Ventricular Dysplasia: Autosomal dominant inheritance. Pathologically described by the ventricular myocardial replacement with fat and fibrosis (fibrous elements preferentially involving the right ventricle). Characterized by cardiac failure and arrhythmia are associated.