IPCCC Code: 01.04.04, 01.03.00, 02.03.01, 02.06.02,

07.02.00, 07.10.00, 01.05.01, 09.29.31

 

AEPC Derived Term:     

EACTS-STS Derived Term:    

ICD 10 Term:   

Definition:  NA

Common Synonyms: NA

Commentary: Controversy still attaches to the lesion illustrated in this month's column. There can be no question but that the malformation is well described as showing double inlet left ventricle. It is equally clear from the images that the heart does not have a single ventricle. Tradition has dictated, nonetheless, that the entity was the exemplar of "single ventricle".¹ This problem is one of linguistics rather than anatomy, and is circumvented simply by describing the anomaly as being one example of the functionally univentricular heart.² The only reason that the entity can be justifiably described as having a single ventricle is if the smaller chamber is denied ventricular status. Some still take this stance, having argued that the small chamber is no more than an infundibulum.³ The morphological evidence, however, points to the chamber being an incomplete right ventricle, lacking its inlet component, which self-evidently is committed to the dominant left ventricle.⁴ If the small chamber were truly an infundibulum, then the entirety of the septum separating it from the dominant ventricle would perforce be the infundibular septum. As can be seen from the images, the septum interposing between the big and small chambers has two discrete components. It is now well established that the apical of these two components carries the ventricular conduction tissues,4 and is nourished by septal perforating arteries.⁵ It is a true rudimentary ventricular septum. This fact also relates to whether the small chamber should be described as an incomplete as opposed to a rudimentary right ventricle. Both terms are appropriate. The ventricle is incomplete because it lacks its inlet component.⁶ It is rudimentary because it unequivocally represents the developing right ventricle, as can be seen by the image from the developing mouse heart, in which, like the incomplete right ventricle found in the setting of double inlet left ventricle, the developing right ventricle has yet to acquire its inlet component, but shows obvious apical and outlet parts.

The developers of the EACTS-STS derived version of the IPCCC agree with these concepts, and further agree that the perceived problem is one of linguistics rather than anatomy. They acknowledge that, in the EACTS-STS derived version of the IPCCC, the term “single ventricle” means “functionally univentricular heart”, defined as describing a spectrum of congenital cardiovascular malformations in which the ventricular mass may not readily lend itself to partitioning that commits one ventricular pump to the systemic circulation, and another to the pulmonary circulation.⁷ It follows that a patient may have a heart deemed to be functionally univentricular either because of its anatomy, or because of the lack of feasibility or lack of advisability of surgically partitioning the ventricular mass. Common lesions falling into the category include double inlet right ventricle, double inlet left ventricle, tricuspid atresia, mitral atresia, and hypoplastic left heart syndrome. Other lesions which sometimes may be considered to be a functionally univentricular heart include complex forms of atrioventricular septal defect, double outlet right ventricle, congenitally corrected transposition, pulmonary atresia with intact ventricular septum, and other complex cardiovascular malformations. Whenever possible, however, the lesions should be catalogued using specific diagnostic codes, and not the term “functionally univentricular heart”. (Source: The International Society for Nomenclature of Paediatric and Congenital Heart Disease (ISNPCHD) [http://www.ipccc.net].

References cited:

1. Edwards JE 1977 Discussion. In: Davila JC (ed.) 2nd Henry Ford Hospital international symposium on cardiac surgery. Appleton Century-Crofts, New York, p 242.
2. Jacobs ML, Anderson RH. Nomenclature of the functionally univentricular heart. Cardiol Young 2006; 16 Suppl 1: 3-8.
3. Van Praagh R, Ongley PA, Swan HJC. Anatomic type of single or common ventricle in man. Morphologic and geometric aspects of 60 necropsied cases. Am J Cardiol 1964; 13: 367–386.
4. Anderson RH, Arnold R, Thaper MK, Jones RS, Hamilton DI. Cardiac specialized tissues in hearts with an apparently single ventricular chamber. (Double inlet left ventricle.). Am J Cardiol 1974; 33: 95‑106.
5. Hosseinpour AR, Anderson RH, Ho SY. The anatomy of the septal perforating arteries in normal and congenitally malformed hearts. J Thorac Cardiovasc Surg 2001; 121: 1046-1052.
6. Anderson RH, Mohun TJ, Moorman AFM. What is a ventricle? Cardiol Young 2011; 21 (Suppl 2): 14-22.
7. Jacobs JP, Franklin RCG, Jacobs ML, Colan SD, Tchervenkov CI, Maruszewski B, Gaynor JW, Spray TL, Stellin G, Aiello VD, Béland MJ, Krogmann ON, Kurosawa H, Weinberg PM, Elliott MJ, Mavroudis C, Anderson RH. Classification of the Functionally Univentricular Heart: Unity from mapped codes. Cardiol Young. 2006; 16 (Suppl 1): 9–21.

Modality: Anatomic specimen

Orientation: Four chamber view

Description: This heart is cut in the four chamber echocardiographic plane to demonstrate the double inlet atrioventricular connection (arrows). The atrial chambers are both connected to the dominant left ventricle (LV), which is the only ventricular chamber visible. There is an incomplete and rudimentary right ventricle positioned anterosuperiorly, as shown in the companion image. The right ventricle is incomplete because it lacks its inlet component, which is connected to the dominant left ventricle. (POF-patent oval fossa, RA-right atrium, LA-left atrium)
Contributor: Diane E. Spicer, BS

Institution: The Congenital Heart Institute of Florida (CHIF)

Image Label:  A010404-54a

Source of Image: Van Mierop Archive, University of Florida, Gainesville, FL

Image Certification: pending

AWG Rating: pending

Modality: Anatomic specimen

Orientation: Long axis view

Description: The heart, shown in the image above, has been cut at right angles to the four chamber section. This cut shows the incomplete and rudimentary right ventricle (RudV) lying superiorly and in anterosuperior position. It supports the aorta (A), while the pulmonary trunk (PT) arises from the dominant left ventricle, so that the ventriculoarterial connections are discordant. The aortic arch is interrupted (not well imaged) and the arterial duct (PDA) is widely patent. There is a muscular ventricular septal defect (VSD). (IVS-interventricular septum, RAA-right atrial appendage, LAA-left atrial appendage).
Contributor: Diane E. Spicer, BS

Institution: The Congenital Heart Institute of Florida (CHIF)

Image Label:  A010404-54b

Source of Image: Van Mierop Archive, University of Florida, Gainesville, FL

Image Certification: pending

AWG Rating: pending

Modality: Anatomic specimen

Orientation: Oblique subcostal view

Description: The image shows a developing mouse heart at embryonic day 11.5. The heart has been prepared using the technique of high resolution episcopic microscopy, and the dataset sectioned so as to show the equivalent of the echocardiographic oblique subcostal cut. As can be seen, the developing right ventricle already possesses its apical trabecular component, and supports the ventricular outflow tract. At this stage, however, its inlet is through the embryonic interventricular communication, the atrioventricular canal being exclusively supported by the developing left ventricle. The right ventricular chamber at this stage is analogous to the incomplete and rudimentary anterior chamber found when there is double inlet left ventricle. The dataset was prepared by Dr. Tim Mohun, Medical Research Council, London, United Kingdom, and the image is reproduced with his kind permission.
Contributor: Robert H. Anderson, MD

Institution: Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom

Image Label:  A010404-54c

Source of Image: Timothy J. Mohun, Phd, Medical Research Council, London, United Kingdom

Image Certification: pending

AWG Rating: pending

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