Introduction

In this short book, we will review some of the controversies which persist concerning the most appropriate means of describing congenitally malformed hearts. Although many lesions could be cited as continuing to produce problems of nomenclature, for the purposes of our discussion, we will limit ourselves to four malformations. The first is the one in which concepts derived from development have, perhaps, produced the most confusion. This is the variant of atrioventricular septal defect which exists in tandem with a common atrioventricular junction. In our approach to this lesion, as with the subsequent malformations, we will show how concepts derived from presumed, albeit unproven, morphogenetic mechanisms have produced markedly inappropriate accounts of the underlying anatomy. The other lesions we will then address are those hearts which are found in the setting of isomeric atrial appendages, the time-honoured malformation of tetralogy of Fallot, where we will discuss its vexed relationship with double outlet right ventricle, and the hearts which are unified because they possess a univentricular atrioventricular connection. In our approach to all these lesions, we will make continued reference to certain common philosophic principles. In this introduction, therefore, we will chart the anatomic background to these principles which guide our analysis, discussing specifically the morphologic method and the sequential segmental approach.