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© 2007 Elsevier. All rights reserved. The simplest method for the categorization of
com-plex congenital cardiac anomalies is to group them into cyanotic and non-cyanotic categories. Cyanosis is usu-ally either a result of systemic venous return bypassing the pulmonary circulation and re-entering the sys-temic circulation without oxygenation or a result of diminished pulmonary flow caused by pulmonary stenosis or atresia. The former condition is caused by discordant connection of the cardiac segments at the atrial–ventricular or the ventricular–arterial level. By assembling the three cardiac segments, we can simply classify variant complex hearts into four sub-groups. According to the concordance or discordance of the three cardiac segments, we can simplify the variant sets into a simple table. From this simple clas-sification, we can easily understand hemodynamic physiology and establish the best mode of treatment.
METHODS AND
RESULTS
To clarify variant complex congenital heart diseases (CHDs), Van Praagh introduced segmental sets to clas-sify the majority of CHDs [1]. He used the visceroatrial situs status including situs solitus (S) and situs inver-sus (I), ventricular looping status (D-loop and L-loop), and the two great arterial relationships (S-, I-, D-, and L-position) to code complex hearts using a simple sym-bol {--,--,--}, but this code still entails some confusion to clearly understand what it signifies. For cardiac anomalies, the most important influential factors are the circulatory status and the severity of structural anomalies. To understand the circulatory physiology, we attempted to categorize CHDs into four groups according to the atrial–ventricular and ventricular– arterial status. From the connections between the atrial– ventricular and the ventricular–arterial segments, we can assemble the complex cardiac anomalies into four subgroups: (1) atrial–ventricular (A–V) concordance with ventricular–arterial (V–A) concordance as no discordance is Group A; (2) atrial–ventricular dis-cordance with ventricular–arterial condis-cordance as A–V discordance is Group B; (3) atrial–ventricular concordance with ventricular–arterial discordance as Received: May 30, 2006 Accepted: August 18, 2006
Address correspondence and reprint requests to: Dr Chao-Chi Chiu, Division of Cardiovascular Surgery, Department of Sur-gery, Kaohsiung Medical University Hospital, 100 Shih-Chuan 1stRoad, Kaohsiung 807, Taiwan.
E-mail: [email protected]
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Huai-Min Chen, Po-Chih Chang, Meng-Shin Lee,1Jin-Ren Wu,1and Chao-Chi Chiu
Division of Cardiovascular Surgery, Department of Surgery, and 1Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
To clarify the variant complex congenital cardiac defects, Van Praagh introduced a system of segmental sets to classify the majority of congenital heart diseases, but the code system entails some confusion for complete understanding. We attempted to recategorize the variant sets into four subgroups according to the connection of the atrial–ventricular and ventricular–arterial segments. This complexity can simply be grouped into four subgroups with regularities. From a simple table so formed, we can quickly ascertain the hemodynamics and the circulatory physi-ology, and therefore quickly determine the treatment protocol for variant complex hearts.
Key Words:anatomically corrected malposition, cardiac sets, concordance, discordance (Kaohsiung J Med Sci 2007;23:30–3)
Easy category for complex cardiac connections
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V–A discordance is Group C; and (4) atrial–ventricular discordance with ventricular–arterial discordance as double discordance is Group D.
In CHDs with atrial situs solitus with ventricular D-loop ({S,D,--}), this combination will present the condition of atrial–ventricular concordance and four types of anatomies including {S,D,S}, {S,D,I}, {S,D,D}, and {S,D,L}. In {S,D,S}, the ventricular–arterial rela-tionship is concordance, so this type of heart can be categorized as Group A. In {S,D,D}, the ventricular– arterial relationship is V–A discordance with trans-position of the great arteries (TGA), so it can be categorized as Group C. In {S,D,I}, it is V–A concor-dance and is grouped as Group A but with the char-acter of isolated infundibulo-arterial inversion [2]. In {S,D,L}, there are two conditions in existence. One is ventricular–arterial concordance, which is character-ized by anatomically corrected malposition of the great arteries ({S,D,L}-ACM), and this can be catego-rized as Group A; the other is ventricular–arterial dis-cordance with the character of TGA ({S,D,L}-TGA) [3], and this can be categorized as Group C. {S,D,S} is most frequently seen in the normal circulatory heart, but may exist in rare cases of posterior TGA in which the aorta originates from the right ventricle, and the aorta is located rightward and posteriorly to the pulmonary artery.
In atrial situs solitus with ventricular L-loop, this combination will present the physiology of atrial– ventricular discordance, and there are four combina-tions including {S,L,S}, {S,L,I}, {S,L,D}, and {S,L,L}. In {S,L,S} and {S,L,I} hearts, the ventricular–arterial relationship is V–A concordance, so the two groups can be categorized as Group B, but {S,L,S} means isolated ventricular inversion [4] and {S,L,I} means isolated atrial inversion [5,6]. In {S,L,L}, the ventricular– arterial relationship is V–A discordance with TGA, so it can be categorized as Group D and characterized as
congenitally corrected TGA. In {S,L,D}, there exists two subgroups: one is V–A concordance with the character of anatomically corrected malposition of the great arteries ({S,L,D}-ACM) [5] and categorized as Group B, and the other is a rare type of V–A dis-cordance with congenitally corrected TGA ({S,L,D}-ccTGA) [3], and categorized as Group D.
In the condition of atria situs inversus, it will be the mirror images of atrial situs solitus. The same conditions exist in ventricular L-looping versus ven-tricular D-looping. We summarize the variant cardiac sets below and in Tables 1 and 2.
• Group A (no discordance): serial circulation with-out cyanosis, no need for treatment.
• Group B (A–V discordance): parallel circulation with cyanosis, needing atrial switch operation. • Group C (V–A discordance): parallel circulation
with cyanosis, needing arterial switch operation. • Group D (double discordance): serial circulation,
needing double switch operation for total correction. Some rare entities such as atrioventricular valvular dysplasia as in tricuspid atresia, the single ventricu-lar heart as in hypoplastic left heart syndrome, and other outlet malconnection as in double outlet right or left ventricle are not suitable for these categories.
D
ISCUSSIONThe problem when attempting to group the variant cardiac codes into a simple table is how to categorize the types of {S,D,L} and {S,L,D}. Except for the two types, every set in the biventricular heart has its own unique circulatory physiology, such as {S,L,L} which stands for A–V discordance and V–A discordance (the so-called ccTGA) and {S,D,D} which stands for A–V concordance and V–A discordance (the so-called complete TGA), but in types of {S,D,L} and {S,L,D}, Table 1.Cardiac segmental relationship
Ventricular–arterial concordance Ventricular–arterial discordance
Atrial–ventricular concordance {S,D,S}/{I,L,I} {S,D,D}-TGA/{I,L,L}
{S,D,L}-ACM/{I,L,D} {S,D,L}-TGA/{I,L,D}
{S,D,I}-IIAI/{I,L,S}
Atrial–ventricular discordance {S,L,S}-IVI/{I,D,I} {S,L,L}-ccTGA/{I,D,D}
{S,L,I}-IAI/{I,D,S} {S,L,D}-ccTGA/{I,D,L}
{S,L,D}-ACM/{I,D,L}
ACM = anatomically corrected malposition; IIAI = isolated infundibulo-arterial inversion; IVI = isolated ventricular inversion; IAI = isolated atrial inversion; TGA = transposition of the great arteries; ccTGA = congenital corrected transposition of the great arteries.
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there are two different circulations in existence in the biventricular heart.
In {S,D,L}, two distinct circulatory physiologies are found: one is ACM and the other is {S,D,L}-TGA. Twisting of the conotruncus in one direction and of the ventricular loop in the opposite direction appears to be of central importance in the morpho-genesis of all types of ACM. In {S,D,L}-ACM, the conotruncus twists rightward instead of leftward. Persistence and growth of the subaortic part of the conus results in aortic-atrioventricular separation and fibrous discontinuity, and absorption of the sub-pulmonary part of the conus permits sub- pulmonary-atrioventricular proximation and fibrous continuity [7]. In {S,L,D}-ACM, the same theory appears to be able to explain this entity. However, if there is pres-ence of extensive levoposition of conotruncus with persistence of subaortic conus, and the aorta is located anteriorly and leftward to the pulmonary artery, the physiology of {S,D,L}-TGA will present [3]. In con-trast, if there is presence of extensive dextroposition of conotruncus with massive subaortic conus, and the aorta is located anteriorly and rightward to the pulmonary artery, {S,L,D}-ccTGA will present.
From these simple categories, we can quickly ascer-tain the cardiac hemodynamics and circulatory phys-iology, and therefore quickly determine the treatment protocol for variant complex hearts. The prime infor-mation we need to know is the situs status of the atrium, the ventricular position, and the relationship of the great arteries, all of which can easily be obtained
by noninvasive echocardiography. Our system of clas-sification may reduce the confusion of medical stu-dents and inexperienced physicians alike in diagnosis of congenital cardiac anomalies. The exceptions not suitable for this system are the conditions of single ventricle and some types of double outlet right/left ventricle, but almost all types of biventricular cardiac anomalies are suited to this system of classification.
R
EFERENCES1. Van Praagh R. The segmental approach to diagnosis in congenital heart disease. Birth Defects: Original Article
Series 1972;Vol III, 5:4–22.
2. Foran RB, Becourt C, Nanton MA, et al. Isolated infundibulo-arterial inversion {S,D,I}: a newly recog-nized form of congenital heart disease. Am Heart J 1988;116:1337–50.
3. Van Praagh R. Transposition of the great arteries: his-tory, pathologic anatomy, embryology, and surgical considerations. Cardiac Surgery: State of the Art Reviews. Philadelphia: Hanley & Belfus, 1991;Vol 5:1, 7–82. 4. Snider AR, Enderlein MA, Feitel DF, et al. Isolated
ven-tricular inversion: two-dimensional echocardiographic findings and a review of the literature. Pediatr Cardiol 1984;5:27–33.
5. Pasquini L, Sander SP, Parness I, et al. Echocardio-graphic and anatomic findings in atrio-ventricular discordance with ventricular-arterial concordance. Am
J Cardiol 1988;62:1256–61.
6. Clarkson PM, Brandt PWT, Barratt-Boyes BG, et al. Isolated atrial inversion. Am J Cardiol 1972;29:877–81. 7. Van Praagh R, Durnin RE, Jockin H, et al. Anatomically
corrected malposition of great arteries {S,D,L}. Circulation 1975;51:20–31.
Table 2.Circulatory relationship*
V–A concordance V–A discordance
*The arrows indicate the direction of blood flow. A–V = atrial–ventricular; V–A = ventricular–arterial; RA = right atrium; RV = right ventricle; PA= pulmonary artery; AO = aorta; LV = left ventricle; LA = left atrium.
A–V concordance
A–V discordance
RA RV PA AO LV LA No treatment (Group A)
Atrial switch (Group B) RA LV AO LA RV PA
Double switch (Group D) RA RV AO LA LV PA
RA LV PA AO RV LA Arterial switch (Group C)
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