Uhl anomaly

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| name = Uhl anomaly

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| caption = Uhl anomaly is inherited via autosomal dominant manner

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Uhl anomaly is a rare cardiac malformation that was first identified by Dr. Henry Uhl in 1952. It is characterized by the absence of the right ventricle (RV) myocardium, either entirely or partially, and the replacement of the RV myocardium by nonfunctional fibroelastic tissue that resembles parchment.{{cite journal |last1=Uhl |first1=Henry |title=A previously undescribed congenital malformation of the heart: almost total absence of the myocardium of the right ventricle |journal=Bulletin of the Johns Hopkins Hospital |date=September 1952 |volume=91 |issue=3 |pages=197–209 |pmid=12978573}} As of 2010 less than 100 cases have been reported in literature.{{cite journal | last1=Hoschtitzky | first1=Andreas | last2=Rowlands | first2=Helen | last3=Ilina | first3=Maria | last4=Khambadkone | first4=Sachin | last5=Elliott | first5=Martin J. | title=Single Ventricle Strategy for Uhl's Anomaly of the Right Ventricle | journal=The Annals of Thoracic Surgery | publisher=Elsevier BV | volume=90 | issue=6 | year=2010 | issn=0003-4975 | doi=10.1016/j.athoracsur.2009.12.084 | pages=2076–2078| pmid=21095379 }}

Patients will typically present as infants with right-sided heart failure.{{cite journal | last1=Richardson | first1=J.D. | last2=Teo | first2=K.S.L. | last3=Bertaso | first3=A.G. | last4=Wong. | first4=D.T.L. | last5=Disney | first5=P. | last6=Worthley | first6=S.G. | title=Uhl's anomaly | journal=International Journal of Cardiology | publisher=Elsevier BV | volume=154 | issue=2 | year=2012 | issn=0167-5273 | doi=10.1016/j.ijcard.2011.05.005 | pages=e36–e37| pmid=21640406 }} Atrial right-to-left shunting is frequently observed as the cause of cyanosis.{{cite journal | last1=Azhari | first1=Nawal | last2=Assaqqat | first2=Mervat | last3=Bulbul | first3=Ziad | title=Successful surgical repair of Uhl's anomaly | journal=Cardiology in the Young | publisher=Cambridge University Press (CUP) | volume=12 | issue=2 | year=2002 | issn=1047-9511 | doi=10.1017/s1047951102000410 | pages=192–195| pmid=12018730 }}

Typically, magnetic resonance imaging, computed tomography, and echocardiography are used to make the diagnosis.{{cite journal | last1=Cammalleri | first1=Valeria | last2=Forcina | first2=Marco | last3=Pugliese | first3=Luca | last4=Romeo | first4=Francesco | last5=Floris | first5=Roberto | last6=Chiocchi | first6=Marcello | title=Uhl Anomaly in Asymptomatic Adult Woman | journal=Circulation: Cardiovascular Imaging | publisher=Ovid Technologies (Wolters Kluwer Health) | volume=12 | issue=2 | year=2019 | issn=1941-9651 | doi=10.1161/circimaging.118.008277 | page=| pmid=30700135 }}

Signs and symptoms

Infants may exhibit severe cyanosis and right heart failure at birth, though these conditions may get better as pulmonary vascular resistance decreases. The main clinical features in older patients are right heart failure symptoms and signs.{{cite book | last=Cheung | first=Yiu-fai | title=Congenital and Paediatric Acquired Heart Disease in Practice | chapter=Uhl Anomaly | publisher=Springer Nature Singapore | publication-place=Singapore | date=2023 | isbn=978-981-99-2861-3 | doi=10.1007/978-981-99-2862-0_26 | pages=271–273}}

Causes

Although the precise cause of Uhl's anomaly is unknown, there have been reports of primary nondevelopment of myocytes, selective apoptosis, and cardiomyocyte overexpression of vascular endothelial growth factor.{{cite journal | last=Uhl | first=Henry S.M. | title=Uhl's Anomaly Revisited | journal=Circulation | publisher=Ovid Technologies (Wolters Kluwer Health) | volume=93 | issue=8 | date=April 15, 1996 | issn=0009-7322 | doi=10.1161/01.cir.93.8.1483 | pages=1483–1484| pmid=8608612 }}{{cite journal | last1=Feucht | first1=M. | last2=Christ | first2=B. | last3=Wilting | first3=J. | title=VEGF induces cardiovascular malformation and embryonic lethality. | journal=The American Journal of Pathology | date=1997 | publisher=American Society for Investigative Pathology | volume=151 | issue=5 | pages=1407–1416 | pmid=9358767 | pmc=1858086 }} A sporadic mutation could indicate that genetics is the underlying cause.{{cite journal | last1=Gerlis | first1=L M | last2=Schmidt-Ott | first2=S C | last3=Ho | first3=S Y | last4=Anderson | first4=R H | title=Dysplastic conditions of the right ventricular myocardium: Uhl's anomaly vs arrhythmogenic right ventricular dysplasia. | journal=Heart | publisher=BMJ | volume=69 | issue=2 | date=February 1, 1993 | issn=1355-6037 | doi=10.1136/hrt.69.2.142 | pages=142–150| pmid=8435240 | pmc=1024941 }}

Mechanism

The pathophysiological outcome of Uhl anomaly involves compromised diastolic filling and right ventricular contraction. Systemic venous congestion and elevated right atrial and systemic venous pressure are the results of right ventricular failure. High pulmonary vascular resistance newborns may develop functional pulmonary atresia (a result of ineffective right ventricular forward flow). Cyanosis is caused by a right-to-left shunting of blood through the patent oval foramen.

Diagnosis

Myocardial biopsies can confirm the diagnosis, which is often established by imaging tests like cardiac magnetic resonance imaging or echocardiogram.{{cite journal | last1=Ganczar | first1=Joanna | last2=English | first2=Robert | title=Uhl′s anomaly: Absence of the right ventricular myocardium | journal=Annals of Pediatric Cardiology | publisher=Medknow | volume=8 | issue=1 | year=2015 | pages=71–73 | issn=0974-2069 | doi=10.4103/0974-2069.149529 | doi-access=free | pmid=25684894 | pmc=4322408 }}

Right atrial and right ventricular dilatation is the cause of the cardiomegaly seen on the chest radiograph. The lung fields of newborns with functional pulmonary atresia and high pulmonary vascular resistance appear oligaemic.

Right ventricular and right atrial dilatation is evident on the electrocardiogram. One can observe an epsilon (ε) wave in the right praecordial leads.

An echocardiographic evaluation reveals a thin free wall of the right ventricle without any myocardium, reduced contractility and restricted ventricle filling, dilation of the right atrium, and normal tricuspid valve attachment to the right atrioventricular junction.

Global dyskinesia of a thin-walled right ventricle, absence of myocardium at the right ventricular free wall, lack of fibrofatty infiltration, normal tricuspid valve attachment to the right atrioventricular junction, and normal left ventricular myocardium are all indicative of cardiac magnetic resonance imaging findings.

Histopathologically, nonfunctioning fibroelastic tissue replaces the myocardial layer, giving the right ventricular free wall a parchment-like appearance.{{cite journal | last1=Chounoune | first1=Reginald | last2=Lowry | first2=Adam | last3=Ramakrishnan | first3=Karthik | last4=Pearson | first4=Gail D. | last5=Moak | first5=Jeffrey P. | last6=Nath | first6=Dilip S. | title=Uhl's anomaly: A one and a half ventricular repair in a patient presenting with cardiac arrest | journal=Journal of the Saudi Heart Association | publisher=Saudi Heart Association | volume=30 | issue=1 | year=2018 | issn=1016-7315 | doi=10.1016/j.jsha.2017.03.011 | pages=52–54| pmid=29296065 | pmc=5744023 }}

Other anomalies that can result in RV dilatation, such as Ebstein anomaly, RV arrhythmogenic dysplasia, pulmonary atresia, and anomalous pulmonary venous return, are included in the differential diagnosis of Uhl anomaly.{{cite journal | last1=Caruso | first1=Settimo | last2=Cannataci | first2=Christine | last3=Romano | first3=Giuseppe | title=Case 288: Uhl Anomaly | journal=Radiology | volume=299 | issue=1 | date=2021 | issn=0033-8419 | doi=10.1148/radiol.2021192475 | pages=237–241| pmid=33750225 }}

Treatment

When the pulmonary vascular resistance has become high and the newborn has severe cyanosis soon after birth, a brief intravenous prostaglandin E infusion is recommended. In most cases, diuretics are necessary for congestive right heart failure. Various surgical techniques have been used, such as: (1) one-and-a-half ventricular repair alongside partial right ventriculectomy and bidirectional Glenn shunt; (2) right ventricular exclusion alongside atrial septectomy as well as a bidirectional Glenn shunt (superior cavopulmonary anastomosis); and (3) cardiac transplantation.

References

External links

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| ICD11 = {{ICD11|LA88.Y}}

| ICD10 = {{ICD10|Q24.8}}

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| OMIM = 107970

| MeshID = C536932

| DiseasesDB = 33469

| SNOMED CT = 2829000

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Category:Congenital heart defects

Category:Rare diseases