Echo-morphological correlates concerning the functionally univentricular heart in the setting of isomeric atrial appendages

Abstract

It has long been known that the most complex combinations of cardiac malformations are those found in the setting of the so-called “splenic syndromes”.1 Many aspects of these syndromes have been controversial over recent years, not least the presence or absence of features of isomerism within the heart.2,3 Recent experience with genetic manipulation of mice, nonetheless, has now shown that it is possible to generate unequivocal evidence of cardiac isomerism, particularly in those animals which show features of right isomerism when the genes responsible for morphologically leftness are knocked out.4 Furthermore, when the crucial philosophical principle known as the “morphological method”5 is applied to the hearts of patients known to have visceral heterotaxy, it is equally clear that patients falling within these groups, when judged on the extent of the pectinate muscles relative to the atrioventricular junctions, exhibit isomerism of either the morphologically right or left atrial appendages.3