Introduction
Any form of anomaly associated with the heart can have a more significant impact on how it works. Anomaly denotes a condition where the structure or function of the organ exhibits significant deviation from what is identified as normal. Uhl anomaly is one such condition where there is anomalous development of the heart, which has occurred during the intrauterine (within the womb) stage. Hence the person will be born with the defect. However, the extent of the anomaly differs on an individual basis. The manifestations of Uhl anomaly closely correlate with the degree of defect or fault associated with the cardiac structure.
What Is Uhl Anomaly?
Uhl anomaly is a peculiar, unfamiliar, inborn cardiac defect that can pave the way for various cardiac complications. It interferes with the working mechanism of the heart. Dr. Henry Uhl first demonstrated it and hence the name Uhl anomaly. It is also known by the term Uhl's anomaly. In this condition, the affected individuals possess defectively formed hearts.
The human heart encompasses different compartments, specifically two upper and two lower compartments. The upper compartments or chambers are medically called atrium, and the lower ones are called ventricles. Each of the upper and lower chambers will be on the right and left sides. To precisely identify the champers, it is often emphasized along with the side - right ventricle, right atrium, left ventricle, and left atrium. Heart muscles are the basic foundations of all these chambers, known as cardiac musculature. The walls of these compartments encompass three distinct layers called endocardium, myocardium, and epicardium, forming the inner, middle, and outer layers, respectively.
In the Uhl anomaly, trouble is with the right ventricle, where the person elicits a significantly weakened right ventricle, which is prone to develop various cardiac complications. Studies have reported a remarkable preference among the male population rather than the female population.
What Leads to the Development of the Uhl Anomaly?
The Uhl anomaly arises due to a defect in the cardiac musculature that structures the heart's right ventricle. Here the middle muscle layer of the right ventricle (myocardium) will go missing either wholly or partially, leaving the other two layers in close approximation. The outer and the inner layer unite in the absence of the middle layer giving rise to a rigid, inflexible ventricular wall. The exact mechanism triggering this abnormal right ventricle formation is still under discussion. Certain hypotheses suggest that the Uhl anomaly arises due to some developmental error during pregnancy. Impairment and destruction of the myocardial muscle cells in the right ventricle following heart development are believed to be yet another underlying etiology. However, there is no conclusive evidence regarding both hypotheses.
What Are the Symptoms Associated With Uhl Anomaly?
Though it is an inborn condition, at times, it remains undetected for some time due to the absence of apparent manifestations. However, in most patients, detectable symptoms and signs are elicited within the childhood stage, particularly in the newborn stage. Some of the frequently encountered manifestations of Uhl anomaly include the following:
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Congestive Cardiac Failure (CCF): Congestive cardiac failure is a medical condition where the heart fails to drive out sufficient blood to meet the body's demand for blood and oxygen. The rigidity and stiffness of the right ventricle in the Uhl anomaly contribute to a minimal contraction in the right ventricle, thus slowing down the oxygenation of the blood as the blood from the right ventricle is supposed to be driven to the lungs to get it loaded with oxygen molecules. Thus the entire blood pumping efficiency of the heart will get affected.
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Arrhythmia: Arrhythmia develops when the heart loses its rhythm and pattern in the beating. In the Uhl anomaly, the stiffness of the right ventricles creates strain in the heart to produce contractions in the left ventricle. As a result, the left ventricular contraction cannot keep pace with the heart's normal beating rate, eventually leading to ventricular arrhythmias.
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Pronounced Hike in the Right Atrial Pressure: As sufficient blood cannot flow out of the right ventricle, the right atrium tends to house more blood volume, elevating its pressure. The enhanced dimension of the right ventricle is also reported with Uhl anomaly.
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Cyanosis: In certain patients, the build-up of right atrial pressure, along with defects in the wall separating the atrium and ventricle (atrioventricular septal defect), forces the blood to seep out of the right atrium into the left atrium through the defective septum. This condition is medically called as right to left atrial shunting. When this form of shunting couples with Uhl anomaly, it can bring about cyanosis, where the person elicits blue tinting on the skin. It is an alarming sign that hints at oxygen depreciation in the cells.
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Other Heart Disorders: Uhl anomaly is often seen in line with co-existing heart diseases like valvular heart diseases and cardiac abnormalities in connection with the right side of the heart.
How Is the Uhl Anomaly Detected?
The clinical manifestations of the anomaly lie on par with the extent of deformity. The aberrant structure and function of the right ventricle in Uhl anomaly can be promptly detected with the help of diagnostic interventions like cardiac magnetic resonance imaging and echocardiography techniques. Cardiac magnetic resonance imaging aids in identifying the structure and nature of the right ventricular wall, thus guiding the final diagnosis even at an early stage of the condition. Echocardiography clearly shows the functional and structural irregularities associated with the right ventricle. Co-existing valvular and septal defects can also be diagnosed with thoracic echocardiography.
What Are the Treatment Interventions Available for Uhl Anomaly?
Medical management of the condition alone is not fruitful in cases of Uhl anomaly with obvious and evident cardiac manifestations. The surgical interventions are designed in such a way as to preclude blood flow to the faulty right ventricle. Instead, the blood will be directed to the lungs by bridging the cardiac blood vessel (superior vena cava) with the pulmonary artery, eventually creating a new pathway to reach the lungs for oxygenation bypassing the right ventricle. The surgical procedure that bridges the two blood vessels is called a cavopulmonary connection. It is otherwise regarded as the Glenn procedure.
Various surgical approaches are in practice to deal with the Uhl anomaly. The type of surgical approach is selected by considering the patient's age, extent of structural deformity, and functional compromise. In more progressed cases with co-existing cardiac diseases, heart transplantation is advised to extend the patient's longevity.
Conclusion
Uhl anomaly, though a rarely encountered cardiac condition, demands prompt medical attention to restore cardiac functions and to check the progression of life-threatening complications. Impaired functioning of the right ventricle interrupts the cardiac rhythm and eventually deteriorates the efficacy of the other unaffected chambers. Many studies have acknowledged the relation of Uhl anomaly with other cardiac abnormalities, typically involving the right side of the heart. Glenn procedure is the most frequently preferred treatment intervention for Uhl anomaly. Heart transplantation is the last resort for patients detected with Uhl anomaly.
