In their article on common pulmonary vein atresia, Perez et al,Reference Perez, Susheel Kumar, Briceno-Medina, Alsheikh-Ali, Sathanandam and Knott-Craig ¹ from Memphis, Tennessee, discuss the essential difference between atresia of the common pulmonary vein and totally anomalous pulmonary venous connection. They emphasise the rarity of the situation in which the pulmonary vein is formed initially, but then becomes atretic, as opposed to the situation in which all the pulmonary veins drain to a site other than the morphologically left atrium. They also point to the differences between the situations in which there is atresia of individual pulmonary veins in the absence of a pulmonary venous confluence, emphasising the presence of a venous confluence as a factor in the chances of achieving surgical correction. It is this latter feature that is of the most significance, because – as they describe – the pulmonary venous confluence in their three cases was either not recognised during the initial investigation or else shown to be grossly hypoplastic when eventually revealed by investigations other than transthoracic echocardiography. The diagnosis of totally anomalous pulmonary venous connection using echocardiography alone, of course, was a major step forward in improving surgical results for this variant of pulmonary veno-occlusive disease. If there is good evidence of the presence of totally anomalous pulmonary venous connection, it is likely nowadays that most patients will be referred directly for timely surgical correction. The discovery of a grossly hypoplastic venous confluence in the operating room in such instances is unlikely to be viewed with enthusiasm by the operating surgeon.

In their report, Perez et alReference Perez, Susheel Kumar, Briceno-Medina, Alsheikh-Ali, Sathanandam and Knott-Craig ¹ not only describe their own three patients but also provide an excellent overview of all the patients previously described in the English literature with alleged atresia of the common pulmonary vein. As they describe, “The criterion used to define common pulmonary vein atresia was absence of pulmonary venous return to the heart or any major systemic veins as defined by Lucas et al”. This is, indeed, the case, with the precise wording used by the group from Minnesota,Reference Lucas, Woolfrey and Anderson ² in their landmark initial description, being “The term atresia of the common pulmonary vein refers to a pattern of abnormal pulmonary venous development in which the individual pulmonary veins are formed but no connection exists between these veins and the heart or major systemic veins”. There is a problem with this definition, as it is equally applicable to totally anomalous pulmonary venous connection or to atresia of the individual pulmonary veins. In the body of their article, however, Lucas et alReference Lucas, Woolfrey and Anderson ² state “The characteristic anatomic feature in each of the three cases was the absence of a functional connection between the pulmonary veins on the one hand and the left atrium or any other cardiac chamber or systemic vein on the other”. They then continued by qualifying their use of “functional”, writing that “The normally formed pulmonary veins were observed to converge immediately behind the left atrium, forming a venous confluence that had no outlet for the pulmonary venous blood received from the pulmonary veins”. I would suggest, therefore, that the initial definition given by Lucas et al,Reference Lucas, Woolfrey and Anderson ² and as repeated by Perez et al,Reference Perez, Susheel Kumar, Briceno-Medina, Alsheikh-Ali, Sathanandam and Knott-Craig ¹ is less than satisfactory. It is the definition used to qualify their use of “functional” that provides the best description of the characteristic phenotype of atresia of the common pulmonary vein. It is this latter definition, therefore, that should now, in my opinion, be used for purposes of future diagnosis of this very rare condition.

It is of further note, however, that only the first of the three cases encountered by the workers in TennesseeReference Perez, Susheel Kumar, Briceno-Medina, Alsheikh-Ali, Sathanandam and Knott-Craig ¹ would likely produce problems in distinction from a primary diagnosis of totally anomalous pulmonary venous connection. This is because, in their additional two cases, the presence of the pulmonary venous malformation was part of a much more complex combination of lesions, with both cases having mirror-imaged atrial arrangement and atrioventricular septal defect with common atrioventricular junction. Although not discussed by the authors, this combination, with no obvious connection of the pulmonary veins to the heart, is suggestive of isomerism of the right atrial appendages. The identification of the atretic pulmonary vein interposing between the hypoplastic venous confluence and the atrial chambers is perhaps supportive of mirror-imagery rather than isomerism, but it would have been of interest to know the bronchial morphology in their last two patients. The experience of the Memphis group in diagnosing this rare lesion, therefore, serves to emphasise the importance of knowledge of the precise phenotype, but perhaps more importantly of providing a precise description of the anatomical features used to determine the phenotype. It also emphasises the need to provide accurate descriptions of the arrangement of each of the systems of abdomino-thoracic organs, including the atrial appendages, so as to permit accurate sequential segmental diagnoses.