Isomerism of the right atrial appendages: Clinical, anatomical, and microscopic study of a long‐surviving case with asplenia and ciliary abnormalities

Abstract

This study describes a case of isomerism of the right atrial appendages (bilateral morphologically right atrial appendages associated with complex congenital cardiac lesions) with ciliary abnormalities. Detailed investigation included gross anatomic dissection, review of the clinical history, and light, confocal, and electron microscopy. Clinically, this 40-year-old, long-surviving male patient had relatively good health until 4 years before death, which was due to cardiac failure. Surgical intervention consisted only of a Blalock-Taussig shunt (anastomosis of the right subclavian artery to the right pulmonary artery) at 6 years of age. Despite the presence of complex cardiac malformations and asplenia, his longevity may be attributed to the connection of the pulmonary veins to the atrium without pulmonary venous obstruction, pulmonary valvar stenosis rather than atresia, no significant atrioventricular valve regurgitation, and no serious infections during his life. Microscopic examination of bronchial epithelium revealed a narrow, disorganized epithelium with abundant goblet cells and short, angulated cilia with a random orientation and possibly an abnormal central microtubule doublet. These abnormalities were not present in controls, and have been noted in primary ciliary dyskinesia (PCD) or Kartagener's syndrome. Because this syndrome has classically been thought to cause random lateralization resulting in a mirror-imaged arrangement of the organs, the occurrence of truly isomeric patterns is not widely recognized. Whereas polysplenia and left bronchial isomerism have been reported to occur in immotile cilia syndrome, this is the first report to present detailed postmortem anatomic evidence of isomerism of the right atrial appendages, right bronchial isomerism, and asplenia in association with microscopy suggesting ciliary abnormalities.

Clinical and genetic aspects of primary ciliary dyskinesia/Kartagener syndrome

“…Heterotaxia syndromes include abdominal situs inversus, polysplenia (left isomerism) and asplenia (right isomerism and Ivemark) syndromes. 111 It is therefore recommended that patients with anomalies consistent with situs ambiguuus or heterotaxy, including congenital heart disease, with neonatal respiratory distress or chronic respiratory tract infections be referred for PCD screening.…”

Right-sided bronchial isomerism diagnosed in adulthood

“…Additionally, a rare long-lived patient with cardiac abnormalities associated with right-sided isomerism was found to have abnormal cilia at post-mortem. 4 The aetiology of right-sided isomerism has been thought to be different from PCD, a diagnosis which is dependent on immotile cilia and usually cilial abnormalities. 9 Furthermore, there are no other descriptions of bronchiectasis in cases of right-sided isomerism, though it is possible that, as right sided-isomerism frequently results in early mortality from cardiac anomalies, bronchiectasis may not have had time to develop.…”

“…3 To the best of our knowledge cases of right-sided isomerism are sufficiently rare in adulthood that there are only two other reports in the literature and only one of the patients had bronchial isomerism. 4,5 kEywORdS Right-sided bronchial isomerism, bronchiectasis, respiratory dECLARATION OF INTERESTS No conflicts of interest declared.…”

Left Atrial Appendage Occlusion for Stroke Prevention

“…(12) In a study by Veinot et al which included 500 autopsy cases, 54% of LAA had two lobes and 34% had > 3three lobes with the lobes often lying in different planes. (11) Congenital juxtaposition and isomerism of the atrial appendages are associated with rare congenital anomalies (13)(14)(15). There are similarities between LAA myocardial and ventricular myocardial cells, and the LAA cells resemble skeletal muscle.…”