Surgical Anatomy of Double-Outlet Right Ventricle-A Reappraisal ROBERT H. ANDERSON, MD, MRCPath, ANTON E. BECKER, MD, BENSON R. WILCOX, MD, FERGUS J. MACARTNEY, MB, BChir, FRCP, and JAMES L. WI~INSON MBChB, NIRCP In light of the recent developments in surgical treatment of double-outlet right ventricle, the ana- tomic observations on this lesion were reevaluated. For this revlew, double-owlet right ventricle was diagnosed when more than half of both arterial valves were connected to the same ventricle, al- though appreciating the reasons for using, In a clinIca context, a “90% NW’ rather than the “50% rule” used In this review. Although this ventrlculo- arterlal connection can exist with any segmental combination, most often it is found in the setting of usually arranged atrial chambers (solitus) and atrloventr~~lar concordance. Categorization of this subset Is then done on the basis of the relationships of the arterial trunks. Three main groups stand out: intertwining arterial trunks and “normally related” arterial valves, and parallel trunks, but wtth the aortlc valve to the right side or left side. These groupings give information concerning the site of the ventricular septal defect, which in any group may be perknembranous, muscular or be doubly com- mItted and subarterial. i~und~~tar morphology is also variable, and the proximity of the arterial valves to the roof of the defect is largely determined by the extent of the ventricu!o-infundibular fold. (Am J Cardfol 1983;52:555-559) In this issue of the Journal, Piccoli and colleagues1 from the University of Alabama in Birmingham describe the evolution of their surgical approach to the treatment of double-outlet right ventricle (DORV). They acknowl- edge the significance of the classic study of Lev and colleague9 in influencing their classification, and also refer to our own anatomic study3 in molding their ap- proach to this malformation. We have been mutually influenced by their surgical experience. Several lengthy discussions with the Bi:rmingham group since the pub- lication of our paper have led to subtle but significant shifts of emphasis in our understanding of the mor- phology of DORV. In the face of these changes and the accompanying surgical report,l it seems appropriate to summarize briefly our current views, concentrating on the benefits they may provide for successful surgical treatment. FrOmthaDeparbmeIltOfF%diatriics. cardiothoracic Institute, Smmpton Hospital, London, U.K.:Depemnent of f’athology, Acadamisch h4adisct-1 Cantrum, and interuniversi~ Cardiologyinstitute. Amsterdam, The fMhariands; Divisionof ~io~ac~c Surgery,diverse of North Carolina at ChapelHill, North Carolina; Thoracic Unit. Hospital for Sick Chiidren,London, U.K.; and tha Royal Liverpool Chlidren’sHospital, Liverpool, U.K. Manuscript receivedMay 12, 1983, accepted May 18, 1983. Address for reprints: F’rofeaaor R. H. Anderson. it of PaeMatrica. Cardiothoracic instbta, Srompton Hospital, F&ham Road, London SW3 8HP. U.K. Definition of ruble-Outlet Right Ventricle As Piccoli et all report, we define DORV in terms of a ventri~ulo~~rial connection. In an autopsy study it is much less difficult to determine precisely the con- nection of overriding arterial valves to their underlying ventricles; therefore, we include within this category all hearts in which more than half of the circu~erence of both arterial valves are connected to the morphologi- cally right ventricle, and thus include more anomalies than Piccoli et al within this category. However, we appreciate their reasons for using a “90% rule” rather than the “50% rule.” As far as both groups of investi- gators are concerned, the diagnosis of DORV and te- tralogy of Fallot are not mutually exclusive. Tetralogy of Fallot is diagnosed by its specific outflow tract mor- phology,* which can be found with either a concordant ventriculoarterial connection (aorta connected mostly to the left ventricle) or in the setting of DORV. The finding of a DORV connection does not, therefore, rule out the diagnosis of tetralogy of Fallot. Van Praagh and colleague@ recently argued against this approach. However, we see little advantage in a system in which diagnoses must change according to whether or not a small bundle of inf~dib~~ musculature separates an arterial from an atrioventricular valve. 555