Hearts in which the arterial trunks arise from the morphologically appropriate ventricles, but in a parallel manner, rather than the usual spiralling arrangement, have long fascinated anatomists. These rare entities, for quite some time, were considered embryological impossibilities, but ongoing experience has shown that they can be found in various segmental combinations. Problems still exist about how best to describe them, as the different variants are often described with esoteric terms, such as anatomically corrected malposition or isolated ventricular inversion. In this review, based on our combined clinical and morphological experience, we demonstrate that the essential feature of all hearts described in this manner is a parallel arrangement of the arterial trunks as they exit from the ventricular mass. We show that the relationship of the arterial roots needs to be described in terms of the underlying ventricular topology, rather than according to the arrangement of the atrial chambers. We then discuss the importance of determining atrial arrangement on the basis of the morphology of the appendages, following the precepts as set out in the so-called “morphological method” and distinguished according to the extent of the pectinate muscles relative to the atrioventricular junctions as opposed to basing diagnosis on the venoatrial connections. We show that, when approached in this manner, the various combinations can be readily diagnosed in the clinical setting and described in straightforward way.

We have re-investigated an unusual cardiac specimen with juxtaposition of the atrial appendages. The original description dates to 1962, when the autopsy was performed at the Children’s Memorial Hospital in Chicago, now Ann & Robert H. Lurie Children’s Hospital of Chicago. The heart was subsequently stored in the Farouk S. Idriss Cardiac Registry at the same institution. The specimen shows usual atrial arrangement, but with the morphologically left appendage juxtaposed in a rightward manner, passing behind the heart rather than through the transverse sinus so as to reach its location inferior to the morphologically right appendage. The heart also demonstrated an inter-atrial communication between the cavities of the juxtaposed left appendage and the morphologically right atrium. We provide a detailed description of the morphology, and provide images of this lesion, which to the best of our knowledge has not previously been described.

We report a case of tricuspid atresia in which the symptoms underwent spontaneous improvement during childhood, and did not return until the age of 56 after which the patient went into progressive congestive failure and atrial fibrillation. He died at the age of 60, without ever having surgical intervention. Autopsy confirmed the presence of tricuspid atresia due to absence of the right atrioventricular connection, and also revealed partial left juxtaposition of the atrial appendages, an atrial septal defect in the oval fossa, rudimentary right ventricle, double outlet left ventricle with anterior aorta (anatomically corrected malposition), subvalvar and valvar pulmonary stenosis, dilation of the pulmonary arteries, patent arterial duct and major systemic to pulmonary collateral arteries.

It was considered that the development of the systemic to pulmonary arterial anastomoses probably accounted for the initial remission of symptoms, whilst the obstruction of the pulmonary outflow tract prevented the development of any significant degree of pulmonary hypertension in the presence of double outlet left ventricle.

Cardiac malformations are very rare in which the great arteries arise from their appropriate ventricles, but are abnormally related to each other. Here, we present a patient with mirror-imaged atrial arrangement and a left-sided heart who has parallel arterial trunks with discordant atrioventricular and concordant ventriculo-arterial connections. The ventricles were related in supero-inferior fashion, the left ventricle being anterior and superior, this being an additional feature which, to the best of our knowledge, has not previously been described in this setting.