Fortuitous Discovery of Partial Uhl Anomaly in a Male Adult

Abstract

W e report the case of a 44-year-old man referred to our institution for suspicion of arrhythmogenic right ventricular (RV) cardiomyopathy. Both familial and personal medical histories were unremarkable, except the notion of a slight unexplored heart murmur during childhood. He decided to undergo a "40s" medical checkup. On presentation to the general practitioner, he had described a slight fatigue for 8 months without concomitant stress. Physical examination revealed no abnormality. ECG showed a type I atrioventricular block and a complete right bundle-branch block ( Figure 1A). Transthoracic echocardiography showed an unusual left ventricle (LV) with a leftward curveted interventricular septum (IVS) and preserved global and segmental LV systolic function, suggestive of high systolic RV pressure or takotsubo cardiomyopathy ( Figure 1B and Movie I in the onlineonly Data Supplement). However further analysis showed normal systolic pulmonary artery pressure and LV filling pressures. The apical 4-chamber view showed an abnormal RV with an aneurysm-like shape of the basal lateral free wall ( Figure 1B and Movie II in the online-only Data Supplement) but with normal kinetics. A first cardiac magnetic resonance image showed biventricular abnormalities, particularly focused on RV wall motion, which justified additional morphological investigations. No abnormal pulmonary venous return was noticed. Invasive coronary angiogram was normal. The patient was later referred to our unit by his attending cardiologist and underwent invasive hemodynamics and biventricular contrast angiography. Cardiac index (pulmonary artery thermodilution) and biventricular volumes were normal. Blood gas content analysis disclosed an intracardiac shunt. RV angiography (Figure 2A and 2B) showed a truncated RV apex and the absence of trabeculations in the anteroapical and inferoapical zones, therefore characterized by a smooth endocardial aspect associated with a major hypokinesia. Other RV segments had normal morphology and kinetics (subtricuspid zone, tricuspid annulus plane systolic excursion, crista supraventricularis, outflow tract, lateral free wall). RV contours showed a marked notch between normal segments and pathological RV apex, also seen retrospectively on magnetic resonance image, contrast echocardiography, and radionuclide angiography ( Figure 1C). During iodine contrast injection, the pigtail catheter induced a transient, clear parietal deformation that retroceded immediately when the catheter was pulled back and fully consistent with a "parchment-like" RV apex (see Figure 2C and 2D and Movie III in the online-only Data Supplement). The LV apex was trabeculated and abnormally attracted by the RV apex, thus deforming the IVS from right to left with a permanent leftward curveted shape but preserved systolic thickening. Fluid-filled pressure measurement at the RV apex showed a clear slowing in both systolic pressure rise and fall with a midsystolic peak of decreased amplitude compared with RV subtricuspid zone. This abnormal pressure s...

Prenatal Diagnosis of Uhl Anomaly with Autopsy Correlation

“…ARVD occurs at a later age being rarely seen before the age of 20. 5 8 Today, we know that ARVD is an inherited genetic disease most frequently due to mutations in desmosome proteins, and pathologically there is replacement of myocardial cells by fibrofatty tissue.…”

“…Selective but unrestrained apoptosis of right ventricular myocytes after complete cardiac development has been postulated to explain Uhl anomaly. 2 8 Bharati and Lev 9 have reported 15 cases of Uhl anomaly and/or ARVD in their huge collection of over 6,300 congenital heart disease and while discussing the etiology, they have concluded that, “the susceptibility may lie in a specific type of abnormal formation of the myocardium itself at the molecular—genetic level during the early stages in the embryo genesis of the heart.” Current trends in the discussion of etiology are indeed in favor of a genetic mutation with a varying intensity in desmosome proteins, resulting in the production of differing severity of Uhl anomaly and/or ARVD type of hearts. This might well be the case here, as we have demonstrated some nuclear abnormality in the present case, the striking feature being the abnormal wiry appearance within the nuclei of the cardiac myocytes which is probably related to genetic mutations.…”

Uhl’s anomaly: a difficult prenatal diagnosis

“…8,9 These partial forms could be underestimated because of their high tolerability, and most of the cases described in adults are diagnosed fortuitously on angiography or autopsy. 8,9 The pathophysiology of Uhl's anomaly is still controversial and the border with entities showing a degenerative aspect of the right ventricular free wall-like arrhythmogenic right ventricular dysplasia remains difficult to establish. The typical histological description in Uhl's anomaly is a transparent right ventricular free wall due to an aposition of the endocardium with the epicardium without intervening myocardium, infiltration, or inflammation.…”

“…The prenatal counselling will then be different, with Uhl’s anomaly having a worse prognosis. Some forms are probably less extensive as Uhl’s anomaly has been described in adults 8 9 These partial forms could be underestimated because of their high tolerability, and most of the cases described in adults are diagnosed fortuitously on angiography or autopsy 8 …”