1. Van Praagh & Vlad Segmental Approach
• Visceroatrial: S-Solitus, I-Inversus, A-Ambiguus
• Ventricular Topology: D loop & L loop
• Great Vessels: S-Solitus, I-Inversus, D-Dextro, L-Levo
2. Anderson Sequential Segmental Approach
• Ventriculoarterial - Concordant
• Cardiac Position - Dextrocardia, Levocardia, Mesocardia
3. Segmental system of Classification of CHD
• Great Veins
• Atrioventricular junctions
• Ventriculoarterial junction
• Great Arteries
Acyanotic: ASD, VSD, PDA, AS, MS, Co-arctation of aorta, AP window
Cyanotic: TOF, TGA, TAPVC, Tricuspid Atresia, HLHS, Ebstein's anomaly, Truncus Arteriosus, PS.
4. AHA Classification
• Septal - ASD, VSD
• Obstructive - PS, AS
• Cyanotic - TOF, TGA
5. Generic Classification
• Hypoplasia: HLHS, HRHS
• Obstructive Defects: PS, AS
• Septal defects
• Cyanotic defects
• Condition of vessel: coarctation of aorta, TAPVC, PAPVC
• Constellation of multiple defects: TOF
6. Other Classification
• L-R shunts
• R-L shunts
• Left Heart Obstructive lesions - MS, AS
• Right Heart Obstructive lesions - PS, TS
• Single Ventricle
• Others - Vascular rings
7. Classification (as in J.Perloff)
• Acyanotic without shunt
• Acyanotic with shunt
8. Classification (as in Hurst)
• Intracardiac communication between systemic and pulmonary circulations - ASD, VSD
• Extra cardiac communication - PDA
• Valvular & Vascular malformations of left side - Coarctation of aorta, Valvular AS. Supravalvular AS, Subvalvular AS, Bicuspid AS.
• Valvular & Vascular malformations of right side - TOF, Ebstein's Anomaly.
• Anomalies of pulmonary venous connection - TAPVC
• Malposition of cardiac structures - TGA, cTGA, DORV
• Coronary anomalies - ALCAPA, coronary AVF.
9. Duke Echocardiographic Classification
A) When chambers and valves are in normal sequence and position - When shunting is predominant - ASD, VSD, PDA
When stenosis is predominant - TA, MA, Coarctation of aorta, TAPVC
B) When not in normal position and sequence Below atria & ventricle - Univentricular heart, ccTGA Between ventricles & great vessels - TOF, DORV, TGA
12. Left to Right shunts are sometimes also classified as
- by Dr Amarja
Congenital heart defects have various forms and can occur in many different combinations. Majority of patients with congenital heart defects survived into adulthood as a result of surgical palliations and intervention which may cause physiologic and anatomic changes. Even without intervention during early life, cardiac structure grows and evolves with the patients. Sequential segmental analysis of the heart enables complex congenital heart malformations to be described in a simple fashion. Most congenital heart malformations occur with normal connections of the cardiac chambers, but the chambers should be analyzed sequentially before the specific lesions are highlighted.Basic principles
All hearts, normal or abnormal, are formed of three segments – the atria, the ventricular mass, and the arterial trunks. The sequential approach begins by determining the position of the atrial chambers. Thereafter, the atrioventricular connection and the ventriculoarterial connection and relations are analyzed. Philosophy of segmental analysis is founded on morphology. Chambers of the heart should be called what they were rather than where they were. Chambers are recognized according to their morphology. Each chamber had morphological characteristic that identified it no matter where it was in relation to the rest of the heart.Sequential segmental analysis using echocardiography
Sequential segmental analysis using echocardiography should include following:
Cardiac position and the apex of the heart should be determined from standard subcostal view (Figure 1a). From this view the diagnosis of dextrocardial (heart is in the right side of chest), levocardia (heart is in the left side of chest apex) or mesocardial (heart is in the middle of chest) can be established. Apex orientation should also be described. For each of above locations, the cardiac apex may point to the left, to the middle, or to the right (Figure 1b).Atrial arrangement
There are four possible atrial arrangements:
Figure2: atrial arrangementMorphological features of left atrium
On echocardiogram, the morphological right or left atrium is best differentiated by their appendages. The right atrium has a triangular appendage and left atrium has a narrow tube-like appendage (Figure 3).
Figure 3: Echocardiographic Features of atria
However appendages are difficult to visualize by transthoracic echocardiography especially in adult patients. Hence this has to be done in an indirect way. The locations of the abdominal aorta and the inferior caval vein (IVC) relative to the spine can provide clues to the atrial arrangement (Figure 4).
Figure 4: Abdominal Sinus, relative positions of aorta and inferior venacava
Atrial situs follows abdominal situs in about 70-80% of cases. From a standard subcostal view with the probe pointing at a right angle to the spine, the abdominal aorta (pulsatile, red colour Doppler) and IVC (non-pulsatile, blue colour Doppler) can be visualized (Figure 5).
Figure 5: Abdominal Situs solitus
When aorta is to the left and IVC is to the right of the spine, there is abdominal situs solitus and corresponding atrial situs solitus. When aorta is to the right and IVC is to the left of the spine, correspond to situs inversus. In isomerism, the great vessels lie to the same side of the spine. In left isomerism, the inferior vena cava lies posterior to aorta and is interrupted and continued via a hemi-azygos vein in majority of cases. In right isomerism, the IVC is anterior to the aorta.Atrioventricular connection
Atrioventricular connection can either be biventricular or univentricular connection. With biventricular connection, it can either be concordant when morphologic right atrium empties into the morphologic right ventricle and morphological left atrium empties into morphologic left ventricle or discordant when morphological right atrium empties to morphological left ventricle and morphological left atrium empties to morphological right ventricle (Figure 6).
Figure 6:Concordant and discordant atrio-ventricular connection
In bi-ventricular heart, the valve usually follows the ventricle. Tricuspid valve connects to right ventricle and mitral valve connects to left ventricle. A common valve guards both right- and left-sided atrioventricular junctions, irrespective of its morphology.
When there is atrial isomerism, the connection is described as ambiguous. In contrast, univentricular atrioventricular connection describes hearts where only one ventricle is connected to the atrial chamber. The majority of hearts with univentricular atrioventricular connection have two ventricles but markedly different in size. There are three possible junction arrangements: double inlet, absent left-sided and absent right-sided atrioventricular connections. Depending on the morphology of the ventricle, it can be a dominant right ventricle, a dominant left ventricle, or morphologically indeterminate ventricle (Figure 7a-c).
Figure 7a:Univentricular atrio-ventricular connections
Figure 7b: Absent left or right Ventricular connection
Figure 7c: Univentricular atrioventricular connections Double inlet ventriclesFeatures of morphological right ventricle
The morphological right ventricle has following features that distinguish it from the morphological left ventricle:
Figure Echocardiographic feratures of atrio-ventricular connectionFeatures of Morphological Left ventricle
The characteristics of morphologic left ventricle are
Figure 9:Univentricular atrioventricular connection - Double inlet left ventricle
Atrioventricular valve morphology can influence type of atrioventricular connection.
A valve overrides when the atrioventricular junction is connected to ventricle on both sides of a septal structure (Figure 10). The degree of override determines the atrioventricular connections. The heart where one AV valve confined to the ventricle and the other AV valve overrides more than 50% will be described as double inlet ventricle (Figure 10). A valve straddles when its tension apparatus is attached to both sides of a septum within the ventricular mass. When the valve straddles, it usually overrides.
Figure 10: Over-riding and straddling right atrioventricular valve
Ventricular topology describes the spatial relationship of one ventricle to the other. There are two topologic patterns that are mirror images of each other. Right and left hand topology. Right hand topology is the normal pattern. Determination of ventricular topology requires first identification of the morphologic right ventricle. If the palmar surface of right hand can be placed on the septal surface, thumb in the inlet and the fingers toward the outlet and the wrist is at the apex, then this is the right –hand pattern. If only the left hand palm can be placed on the septal surface of the right ventricle in the same manner, then this will be described as left hand topology. Ventricular topology allows analysis of the atrioventricular junction in hearts with isomeric arrangement of atrial appendages.Ventriculoarterial connection
There are four possible ventriculoarterial connections: concordant (connection to appropriate ventricle), discordant (connection to inappropriate ventricle), double-outlet (one arterial trunk and more than 50% of the other arterial trunk are connected to the same ventricle, be it of right ventricle, left ventricle or indeterminate morphology) and single outlet (common or solitary arterial trunk). The aorta and pulmonary trunk are distinguished by their branching patterns and origins of the coronary arteries. Pulmonary artery branches into left and right pulmonary arteries. Aorta has coronary arteries taking off from its root and head and neck vessels from aortic arch. A common arterial trunk has a single arterial valve and always gives rise directly to the coronary arteries, at least one pulmonary artery and the majority of systemic arteries. A solitary arterial trunk exists when there are no identifiable intrapericardial pulmonary arteries and collateral arteries arising form the descending aorta supply the lungs (Figure 11-13).
Figure 11: Morphological features of great arteries
Figure 12:Discordant ventriculo-arterial connection
Figure 13: Single outlet ventricleAssociated malformations
The majority of patients with congenitally malformed hearts will have usual chamber combinations. It is the associated malformations plays major role in patients’ clinical presentation. Anomalies of atrial, ventricular and great arteries must be carefully searched for and haemodynamic effect of the lesions must be assessed.
In summary, all hearts can be considered in three segments: the atrial chambers, the ventricular mass and the great arteries. Sequential segmental analysis means to identify the component parts of the heart by their morphology and describe the interconnections in a sequential manner.
Supplement issue: The Feline HeartSequential segmental classification of feline congenital heart disease
Received 31 December 2014. Revised 1 April 2015. Accepted 21 April 2015. Available online 15 January 2016.
Feline congenital heart disease is less commonly encountered in veterinary medicine than acquired feline heart diseases such as cardiomyopathy. Understanding the wide spectrum of congenital cardiovascular disease demands a familiarity with a variety of lesions, occurring both in isolation and in combination, along with an appreciation of complex nomenclature and variable classification schemes. This review begins with an overview of congenital heart disease in the cat, including proposed etiologies and prevalence, examination approaches, and principles of therapy. Specific congenital defects are presented and organized by a sequential segmental classification with respect to their morphologic lesions. Highlights of diagnosis, treatment options, and prognosis are offered. It is hoped that this review will provide a framework for approaching congenital heart disease in the cat, and more broadly in other animal species based on the sequential segmental approach, which represents an adaptation of the common methodology used in children and adults with congenital heart disease.
atrial septal defect
2 Sequential Segmental Approach to Congenital Heart Disease
Morphologically, malformations affecting the heart can be categorized into two broad categories. The first category is the malformations affecting the heart in which the cardiac chambers and the great arteries are normally related and connected. Typical examples are septal defects and valvular stenosis. The second category includes more complex malformations that are characterized by an abnormal relationship between the components of a segment or segments and abnormal connections between cardiac segments. Examples include various forms of so-called single ventricles or univentricular hearts, complete and corrected transposition of the great arteries, and double-outlet ventricles. These complex malformations require a systematic analysis in a step-by-step fashion that is called the sequential segmental approach. 1 –6 The concept of sequential segmental approach was first introduced by Van Praagh et al in 1964. 7 Since then, there have been discussions and debates regarding the system of segmental analysis and its terminology. The most intense and serious debates have been between Richard Van Praagh of Boston, Massachusetts, and Robert H. Anderson of London, UK. Unfortunately, the debates have polarized the pediatric cardiology group into two schools, Van Praaghnians and Andersonians. On reading the published book chapters and articles regarding this important subject, one may be overwhelmed by the semantic controversies and debates. In this chapter, we will introduce the compromised system and terms that we find most useful in day-to-day clinical practice without discussion of the scholastic origins of the terms.Basic Cardiac Segments and Steps of Sequential Segmental Analysis
As discussed in Chapter 1. the heart consists of three morphologically and functionally distinct segments: the atria, the ventricles, and the arterial trunks (Fig. 2.1 ). They are joined together by two connecting units, the atrioventricular junction and the ventriculoarterial junction, both of which are usually guarded by the valves. Each component of each segment of the heart is characterized by its own morphologic characteristics. The components of each segment can be related in various ways, and the components of a segment can be connected to the components of the next segment in various ways. Therefore, there are three facets in the make-up of the heart: the morphologies. the connections. and the relations. 6 Sequential segmental analysis is the systematic approach to the diagnosis of congenital heart disease in which the three facets of the make-up in the heart are analyzed in a segment-by-segment fashion. The major steps of sequential segmental approach include (Fig. 2.2 )
Fig. 2.1 Basic cardiac segments and intervening junctions.
Fig. 2.2 Steps of the sequential segmental approach.Determination of the Visceral Situs and Cardiac Position
Congenital heart disease is common and usually complex when the visceral situs is abnormal or the heart is abnormally positioned. As will be discussed later in this chapter, the visceral situs is highly predictive of the atrial situs, which is called the visceroatrial concordance rule. Therefore, the visceral situs should be determined as the first step of a segmental approach.
Fig. 2.3 Types of visceral and atrial situs. PA, pulmonary artery; SVC, superior vena cava; IVC, inferior vena cava; GB, gallbladder; RA, right atrium; LA, left atrium.
The visceral situs is classified into the situs solitus, situs inversus, and heterotaxy. In situs solitus, the larger lobe of the liver is seen on the right, and the stomach and spleen are seen on the left (Fig. 2.3 ). The abdominal aorta is located posteriorly at the left anterior aspect of the spine, and the inferior vena cava is located more anteriorly on the right as it connects to the right atrium. In situs inversus, this right-left relationship is reversed. Rarely, the arrangement of the abdominal organs does not conform to the orderly and lateralized pattern of the situs solitus or the situs inversus. This condition is called visceral heterotaxy. 3 ,4 Usually visceral heterotaxy is associated with either polysplenia or asplenia. It is important, therefore, to evaluate the splenic status by scrutinizing the perigastric area when the abdominal situs is neither solitus nor inversus. In polysplenia, multiple spleens of similar size are seen behind the stomach as they are aggregated on both sides of the mesogastrium. Occasionally, multiple spleens may be fused to form a single but multilobulated mass. Polysplenia is commonly associated with interruption of the suprarenal segment of the inferior vena cava with continuation through the azygos or hemiazygos venous system. Although it can also occur with any other body situs, interruption is highly suggestive of polysplenia. 8 ,9 In most cases of asplenia, the abdominal aorta and inferior vena cava are juxtaposed on the same side of the spine. 8 –10 In the thorax, visceral heterotaxy is characterized by a symmetric lobation of the lungs and a symmetric branching pattern of the bronchi and pulmonary arteries. Visceral heterotaxy with asplenia is typically associated with a right isomeric arrangement of the lungs, bronchi, and pulmonary arteries, whereas visceral heterotaxy with polysplenia is usually associated with a left isomeric arrangement.
The cardiac positions are classified into levocardia, dextrocardia, and mesocardia according to where the main part of the heart is located relative to the midline (Fig. 2.4 ). With rare exceptions, the main part of the heart is positioned on the side where the cardiac apex is located. In mesocardia, the cardiac apex may point to the right, left, or midline. These terms should not be used for those conditions where the heart is displaced to either side secondary to a noncardiac pathology such as hypoplasia or hyperinflation of a lung. Complex terms, such as dextroversion, levoversion, and dextroposition should be abandoned.
Fig. 2.4 Cardiac positions.Morphologic Identification of the Cardiac Chambers and Great Arteries
After determination of the visceral situs and cardiac position, the cardiac chambers and great arteries are identified according to the morphologic characteristics. In this regard, one should be aware that the adjectives “right” and “left” for the cardiac chambers are not to describe the sidedness within the body, but to describe the morphology of the atria and ventricles. Therefore, the atrium that is located on the right, but shows the morphologic characters of the normal left atrium should be called “the right-sided (morphologically) left atrium.” The morphologic criteria for atrial, ventricular, and great arterial identification are discussed in Chapter 1 and summarized in Tables 2.1. 2.2. 2.3 .Analysis of the Segmental Connections and Relations Determination of the Atrial Situs
The atrial situs means how the atria are related to each other relative to the midline. It is categorized into the situs solitus, situs inversus, right isomerism, and left isomerism (Fig. 2.3 ). As discussed, determination of the atrial situs is based on the morphology of the atrial appendages and the extent of the pectinate muscles relative to the atrioventricular junction. 11 Although these criteria are easy to apply at pathologic examination, they are often inapplicable during diagnostic imaging of living individuals. It is well known, however, that the atrial situs is harmonious with the visceral situs in the majority of cases. Therefore, the atrial situs can be accurately predicted by analyzing the bronchial branching pattern and splenic situs. Lastly, it should be emphasized that an atrioventricular block in the presence of structural heart disease is highly suggestive of left atrial isomerism. 12
Table 2.1Morphologic Criteria for Identification of the Right and Left Atria