Sequential Segmental Approach to Congenital Heart Disease
Samir Shakya1, Palleti Rajashekar2, Saurabh Kumar Gupta1 1 Department of Cardiology, All India Institute of Medical Sciences, New Delhi, India 2 Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi, India
Date of Submission
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Correspondence Address: Dr. Saurabh Kumar Gupta Department of Cardiology, Room No. 9, 8th Floor, Cardio-Thoracic Sciences Centre, All India Institute of Medical Sciences, New Delhi - 110 029 India
Source of Support: None, Conflict of Interest: None
The sequential segmental approach is essential for better understanding of cardiac anatomy in normal and malformed hearts. It is based on a detailed analysis of the three main cardiac segments, namely atria, ventricles, and great vessels, and the two connecting segments, namely atrioventricular and ventriculoarterial connections. Each segment is systematically defined based purely on its morphological characteristics. In most cases, echocardiography is sufficient, but some cases necessitate the use of other imaging modalities. Systematic identification of different segments, connections, and their abnormalities helps in making an accurate diagnosis of congenital heart disease (CHD). This review provides a brief description of the sequential segmental approach for detecting CHD on echocardiography.
How to cite this article: Shakya S, Rajashekar P, Gupta SK. Sequential Segmental Approach to Congenital Heart Disease. J Indian Acad Echocardiogr Cardiovasc Imaging 2020;4:244-52
How to cite this URL: Shakya S, Rajashekar P, Gupta SK. Sequential Segmental Approach to Congenital Heart Disease. J Indian Acad Echocardiogr Cardiovasc Imaging [serial online] 2020 [cited 2021 Apr 13];4:244-52. Available from: https://www.jiaecho.org/text.asp?2020/4/3/244/303948
A systematic segmental analysis of cardiovascular anatomy is essential for optimal management of patients with congenital heart disease (CHD). Understanding cardiac anatomy is integral to the pediatric cardiology training, while it is much less discussed among adult cardiologists and echocardiographers. Nonetheless, it is not uncommon for an adult cardiologist and echocardiographers to encounter a patient with unrepaired or repaired CHD. Therefore, it is important to understand the basics of sequential segmental approach. Besides, the uniform use of such an approach helps in easy communication among team members managing a patient with suspected CHD. For obvious reasons, while most anatomic details are well delineated on echocardiography, it is not always possible to demonstrate all aspects of cardiac anatomy and necessitate the use of other imaging modalities. In this article, we provide a brief description of the sequential segmental approach to cardiac anatomy with an emphasis on echocardiographic evaluation.
Sequential Segmental Analysis
Van Praagh first conceptualized the segmental classification of cardiac anatomy. Their description was limited to relationships of three main cardiac segments, namely, the atrial chambers, the ventricles, and the arterial trunks. Later in the 1970s, Anderson et al. highlighted the importance of morphology of the connecting segments, atrioventricular (AV) and ventriculoarterial (VA) junctions, in defining cardiac malformations. It is also well known that the assessment of each cardiac segment should be strictly based on its morphologic characteristics and not on its location, orientation, and connection with other segments. This assumes greater significance in the setting of CHD, where the variation in the orientation and connection of various cardiac segments is common. The sequential segmental analysis is a 10-step approach for a detailed assessment of “main segments” and “connecting segments” of the heart.
The situs refers to the spatial orientation and sidedness of organs. Normally, visceral organs are lateralized. The arrangement of thoraco-abdominal organs is important as it provides information about the atrial arrangement, thus laying the foundation for further analysis of cardiac morphology (see later).
In situs solitus or usual arrangement, the spleen, pancreas, stomach, and sigmoid colon are located on the left, while the liver, cecum, and appendix are on the right side. The left lung has two lobes with a relatively longer bronchus that lies below the left pulmonary artery (hyparterial). The right lung, in contrast, has three lobes and a wider, shorter bronchus that lies above the right pulmonary artery (eparterial) [Figure 1]. In some cases, the arrangement is a mirror image of the normal. This arrangement is termed as situs inversus although there is no up-down inversion of organs. However, for ease of communication, we will continue to use the terms “situs solitus” and “situs inversus” in this article. Sometimes, thoraco-abdominal organs lack asymmetry, and the arrangement is inconsistent. This arrangement, also known as situs ambiguous or visceral heterotaxy, is commonly associated with the isomerism of atrial appendages (see later) and has high chances of CHD.
Figure 1: The arrangement of thoraco-abdominal organs in situs solitus, situs inversus, and situs ambiguous. Situs solitus has trilobed right lung with eparterial bronchus, bilobed left lung with hyparterial, right-sided liver, and left-sided spleen and stomach. The arrangement in situs inversus is a mirror image of situs solitus. In situs ambiguous or visceral heterotaxy, the liver is in the midline and splenic abnormalities are common. Both the lungs are bilobed or trilobed in the setting of left or right isomerism, respectively
The position of the heart in the chest cavity provides important clues about cardiac anatomy and underlying CHD. Most often, the heart is left-sided in the setting of situs solitus, whereas it lies on the right side if there is situs inversus. The cardiac position other than expected for the thoraco-abdominal situs is associated with a high likelihood of CHD.
The description of the cardiac position includes:
The position of the cardiac mass relative to the midline. The heart can be left-sided (levocardia), right-sided (dextrocardia), or lie in the midline (mesocardia)
The orientation of the long axis (base to apex) of the heart.
In most instances, the cardiac position and base-to-apex orientation are concordant, and it is sufficient to describe the cardiac position. The discrepancy on rare occasion necessitates a description of both features separately.
The identification of cardiac morphology starts from the determination of which atrium is the right atrium (RA) and which is the left atrium (LA). The atria are defined neither by their venous connections nor by the side of the body on which the atrium lies. Instead, it is the morphological features, particularly of the atrial appendage, that defines a chamber as morphologically RA or LA. Based on the morphology of the atrial appendage, the atrial arrangement is classified as:
Usual arrangement or situs solitus: morphological RA located to the right of the morphological LA
Mirror image arrangement or situs inversus: morphological RA located to the left of the morphological LA. This is a left–right inverted arrangement compared to situs solitus
Atrial isomerism or situs ambiguous: both the atriums have morphologically similar appendage. The arrangement can be either right isomerism or left isomerism. This arrangement is commonly associated with disorganized left–right symmetry of abdominal organs and is also known as heterotaxy syndrome.
In clinical practice, it is common to encounter difficulties in the exact localization of atriums. In such a scenario, since a high concordance exists between thoraco-abdominal, bronchial, and atrial situs, the atrial situs is adjudged based on the relative position of the inferior vena cava (IVC) and the aorta. In situs solitus, the aorta is to the left of the spine, and the IVC lies anterior and to the right of the aorta [Figure 2] and [Figure 3] and [Video 1]. In cases with situs inversus, the aorta is to the right with the IVC lying to its left and anterior. On most occasions, drainage of a patent IVC identifies the RA, although rarely it can drain anomalously to the LA. In the setting of left isomerism, sometimes, the infrahepatic portion of the IVC is interrupted, and instead, the blood from the lower body drains via azygos vein, which runs posterior to aorta. The identification of the arrangement of the abdominal situs is readily possible on echocardiography. The assessment of bronchial situs, however, mandates chest X-ray or computed tomography.
Figure 2: The arrangement of abdominal viscera and vessels in situs solitus (a), inversus (b), and ambiguous (c)
Figure 3: Trans-thoracic echocardiogram in subcostal short-axis view from a neonate with situs solitus. The IVC is to the right and Ao is to the left of the vertebral body in situs solitus, while the reverse arrangement is seen in patients with situs inversus [see [Figure 2]]. IVC: Inferior vena cava, Ao: Aorta
In patients with a good acoustic window, it is possible to define the morphology of the atrial appendage. Broadly speaking, an atrium with a triangular appendage with a broad base and a wide mouth is a morphological RA [Figure 4] and [Video 2] and [Video 3]. The LA, on the other hand, has a long, tubular, finger-like appendage with a narrow orifice [Figure 5]a and [Video 4]. The parasternal short-axis view is often sufficient to define the LA appendage. The subcostal long-axis view enables visualization of the RA appendage. Some cases with complex cardiac malformation or poor acoustic window mandate transesophageal echocardiography or other cross-sectional cardiac imaging such as computed tomography or magnetic resonance imaging.
Figure 4: Trans-thoracic echocardiogram in subcostal bicaval view (a) showing the usual location of broad triangular RAA in a child with an atrial septal defect (arrow). (b) Juxtaposed RAA in a neonate with transposition of great arteries in which the RAA is abnormally located on the left side. IVC: Inferior vena cava, LA: Left atrium. RA: Right atrium, SVC: Superior vena cava, RAA: Right atrial appendage
Figure 5: Trans-thoracic echocardiogram in parasternal short-axis view (a) showing normal relation of great arteries with pulmonary valve lying anterior and to the left of the Ao. A tubular, finger-like LAA (broken lines) and origin of the right coronary artery (arrow) are also well seen. (b) The circle and sausage appearance, with the Ao in the center and PA with branching seen to the left of Ao. N: Noncoronary cusp, L: Left coronary cusp, LPA: Left pulmonary artery, R: Right coronary cusp, RA: Right atrium, RPA: Right pulmonary artery, Ao: Aorta, LAA: Left atrial appendage, PA: Pulmonary artery
Apart from atrial situs, it is important to delineate the venous connection to the atrial chambers. A combination of subcostal, thoracic, and suprasternal views is generally sufficient [Figure 4] and [Video 2]. In some cases with difficulty and suspicion of anomalous systemic venous connection, a carefully performed and interpreted saline-contrast echocardiography is extremely useful. Compared to systemic veins, the delineation of pulmonary veins is more challenging. In children and adolescents with normal connections, a modified high parasternal view, also known as crab view, is most useful for defining the connection of all four pulmonary veins. A similar modified parasternal short-axis view also provides details of the common chamber and pulmonary veins in patients with supracardiac and cardiac forms of total anomalous pulmonary venous connection. Obtaining these views in adults is challenging, where the apical four-chamber view and subcostal view are used to delineate the connection of pulmonary veins to LA.
Morphologically, the AV valve represents the ventricular chamber and it is one of the features used to identify a ventricle as right or left. In hearts with concordant AV connections, the tricuspid valve guarding the right AV junction has three leaflets and is positioned distally (apical offsetting) compared to the left-sided bi-leaflet mitral valve [Figure 6] and [Video 5] and [Video 6]. Unlike the mitral valve, the tensor apparatus of the tricuspid valve connects to the ventricular septum. These findings are useful in echocardiographic identification of tricuspid and mitral valves. In the setting of atrioventricular septal defect (AVSD), the AV valve is common with no apical offsetting of the left and the right components of the valve. Since the valve is common and does not possess characteristics of a normal mitral or tricuspid valve, it is better to use the term left and right AV valves, instead of tricuspid and mitral valves. The apical offsetting is also absent in cases with inlet type of ventricular septal defect (VSD) and both AV valves are at the same level [Figure 6]c.
Figure 6: Trans-thoracic echocardiogram in apical four-chamber view (a) showing the normal apical displacement of the tricuspid valve compared to the mitral valve. An excessive apical displacement (>8 mm/m2 in children and >15 mm in adults) of the tricuspid valve indicates Ebstein anomaly (b). Panel c shows lack of apical offsetting of the tricuspid valve in the setting of an inlet ventricular septal defect (star). LA: Left atrium, LV: Left ventricle, RA: Right atrium, RV: Right ventricle
En face view of the AV valves in the subcostal short-axis and the left anterior oblique views helps in identifying the morphology [Figure 7]a and [Video 7]. The parasternal short-axis view at the level of the mitral valve can also be used to study the morphology of mitral valve leaflets [Figure 7]b. A detailed assessment of the AV valves and their tensor apparatus necessitates imaging in multiple echocardiographic views.
Figure 7: Trans-thoracic echocardiogram in subcostal left anterior oblique view (a) showing atrioventricular valves en face with anterior (A), posterior (P), and septal (S) leaflets of the tricuspid valve and anterior (A) and posterior (P) leaflets of the mitral valve. The septal attachment of the tricuspid valve is also well seen. Parasternal short-axis view at the level of the mitral valve (b) showing the anterior and posterior mitral leaflets. AML: Anterior mitral leaflet, LV: Left ventricle, PML: Posterior mitral leaflet, RV: Right ventricle
The next step is to define the AV connection. In normal hearts and most of the malformed hearts, each atrium connects to a morphologically appropriate ventricle, an arrangement known as concordant AV connection. Less commonly, the atrium connects to morphologically inappropriate ventricle which is called discordant AV connection. In the setting of atrial isomerism with both atriums being either left or right, the AV connection is anatomically mixed as one of the atriums will mandatorily connect to morphologically inappropriate ventricle. The connection, nevertheless, is not always physiologically abnormal. For example, it is physiologically normal in case morphologic right ventricle (RV) receives systemic venous blood and morphologic left ventricle (LV) receives blood from the pulmonary veins, irrespective of whether both the atriums are morphologically right or left.
Connection-wise, as highlighted earlier, the AV valves are usually committed fully to one of the ventricles, although, in the setting of single-ventricle physiology, one of the valves may be atresia, e.g., tricuspid atresia and mitral atresia. In some cases, mostly in the presence of a VSD, the AV valve can be connected to both the ventricles. In this regard, the term overriding is used if the valvular annulus overrides the ventricular septum. The degree of override greater than 50% assigns the valve to the ventricle, receiving a greater share of the annulus. The AV valve is termed as straddling when the tensor apparatus is supported by the other ventricle, in addition to the ventricle with the dominant connection., The identification of straddling and overriding of AV valve is important as it is often associated with hypoplasia of the ipsilateral ventricle precluding biventricular surgical repair. Rarely, the AV connection can have both atriums connected to one ventricle (double-inlet ventricle) or one atrium connecting to both the ventricles (double-outlet atrium) creating single-ventricle physiology. [Figure 8] summarizes possible variations in the AV connection.
Figure 8: The variations in atrioventricular connection. AV: Atrio-ventricular
After the determination of the atrial situs, this is the most important step of the segmental analysis. RV has more complex geometry with an apically displaced tri-leaflet tricuspid valve having an attachment to the ventricular septum, coarse trabeculations, and a distinctly trabeculated septal surface, which includes septal and moderator bands [Figure 9] and [Video 8] and [Video 9]. A normal RV has an inlet, apical, and outlet portions with the infundibulum separating the pulmonary valve from the tricuspid valve. The LV is more elliptical and has a smooth septal surface, fine trabeculations, two distinct papillary muscles, and no attachment of bi-leaflet mitral valve to the ventricular septum. The LV has a more acute angle between the mitral and aortic valves bringing both the valves in continuity [Figure 10]a. Among all morphological features, the morphology of the AV valve is most reliable in identifying a ventricle as RV or LV. For obvious reasons, as highlighted earlier, this cannot be used in cases with AVSD and double-inlet ventricle.
Figure 9: Trans-thoracic echocardiogram in apical four-chamber view (a) showing the MB, a characteristic morphologic feature of the RV. (b) Subcostal short-axis view below the level of atrioventricular valves showing a trabeculated RV side of the ventricular septum (arrows) compared to a smooth surface on the LV side. Note right-hand topology with the inlet of RV lying to the right of LV inflow. LA: Left atrium, RA: Right atrium, MB: Moderator band, RV: Right ventricle, LV: Left ventricle
Figure 10: Trans-thoracic echocardiogram in the parasternal long-axis view shows aorto-mitral continuity in a child with a normal heart (a) and aorto-mitral discontinuity (b) with a wedge of tissue (broken line) between the base of the AML and the annulus of the aortic valve in a child with double-outlet RV with subaortic ventricular septal defect (star). AML: Anterior mitral leaflet, Ao: Aorta, LA: Left atrium, LV: Left ventricle, PML: Posterior mitral leaflet, RV: Right ventricle
Once the ventricles are identified, the focus is shifted to the ventricular topology or loop, which defines the spatial relationship of the ventricles., The understanding of the ventricular loop is clinically relevant as it determines the pattern of coronary arteries and the conduction system. The ventricular topology is a morphological concept based on chirality. In d-loop or right-handed topology, the RV permits the placement of the right hand so that the thumb is in the inflow and fingers are in the outflow, while the palmar surface of the hand faces the ventricular septum. This is expected in cases with situs solitus and concordant AV connection. In contrast, in the setting of l-loop or left-handed ventricular topology, the morphological RV can accommodate only the left hand in this fashion. This left-handed topology is expected in the setting of situs inversus and concordant AV connection. Cardiac malformations related to faulty looping such as congenitally corrected transposition of great arteries are common in cases with discordance between the atrial arrangement and ventricular looping. The concept of chirality is difficult to demonstrate on echocardiography. Therefore, despite being inaccurate in a minority of cases, the ventricular topology is defined on the basis of the spatial orientation of the inlet of the ventricles. Thus, for practical considerations, the tricuspid valve lying to the right of the mitral valve is labeled as d-loop or right-hand topology [Figure 9]. The left–right inversion of this arrangement, with the tricuspid valve lying to the left of the mitral valve, is termed as l-loop or left-hand topology.
The infundibulum is the connecting segment between the ventricles and the arterial trunks. In normal hearts, there is a complete subpulmonary conus with muscular separation between the pulmonary and the right-sided tricuspid valves, whereas the subaortic conus is absent, allowing fibrous continuity between the left and noncoronary cusps of the aortic valve and the base of the anterior mitral leaflet [Figure 10]a. In some hearts, the aortic valve is separated from the mitral valve when it is labeled as aorta–mitral discontinuity [Figure 10]b and [Video 10]. In morphological terms, this indicates subaortic conus. Any arrangement other than isolated subpulmonary conus, i.e., bilateral conus, subaortic conus with absent subpulmonary conus, and bilaterally absent conus, is abnormal. A subpulmonary conus is typically absent in the setting of transposition of great arteries (TGA), which in turn results in continuity between the pulmonary valve and the mitral valve, although this is not an essential morphological feature to define TGA [Figure 11]a and [Video 11]. Similarly, bilateral conus is commonly associated with a double-outlet RV but is not necessary for the diagnosis.
Figure 11: Abnormal ventriculoarterial connections. (a) Parasternal long-axis view from an infant with discordant ventriculoarterial connections (transposition of great arteries) with a large subpulmonic ventricular septal defect (star) with pulmonary stenosis. Note the presence of continuity between the mitral valve and pulmonary valve (arrow). (b) Subcostal short axis view in diastole from a child with a common arterial trunk with sinusal origin of main pulmonary artery segment and a large subtruncal ventricular septal defect (star). Ao: Aorta, LA: Left atrium, LV: Left ventricle, PA: Pulmonary artery, RV: Right ventricle
Thus, although the infundibulum provides an important clue about cardiac anatomy, it is not the defining feature of either ventricle or VA connection, and therefore, the morphology of the infundibulum should not be used to define the ventricle or VA connection.
Next, the outflow of the ventricles is examined to determine from which cardiac chamber the great arteries originate. VA connection also determines how the semilunar valves and their respective great vessels align with the underlying ventricles. Assessment of VA connection is easy in most hearts with normal connections. The assessment may be is challenging in the setting of CHDs, especially conotruncal malformations. In cases with coexisting interventricular communication in the outflow region, one of the semilunar valves can override the ventricular septum. Again, in malformations with a possible double outlet of a ventricle, the application of the so-called “50% rule” helps in assigning a valve to one of the ventricles. Like many other morphological principles, this “50% rule” is not easily demonstrable on echocardiography due to the complex three-dimensional (3D) relationship of the ventricles and the great arteries, curved sigmoid shape of the ventricular septum, and rotational and translational cardiac motion. Advanced 3D imaging techniques are superior, but the exact delineation may still be challenging in some complex cases.
Like the analysis of other areas of the heart, the VA alignment should also be solely assessed based on the connection and spatial relationship between the semilunar valves and the underlying ventricles and not on the variable characteristics of ventricular outflow and infundibulum.
Just like AV connection, the VA connection can also be concordant, discordant, or absent. Unlike the AV connection, VA connection cannot be mixed as isomerism of the ventricular chamber is unknown. The connection can also be double outlet when both arterial trunks arise from only one ventricle [Figure 12]. In most conditions, it is the RV that has a double outlet with a minority having double outlet of the LV. There may also be a single outlet from the heart. This group includes a common arterial trunk and a single outlet with atresia of one semilunar valve. In the common trunk, both ventricles are connected via a common arterial valve to this trunk that directly provides systemic, pulmonary, and coronary circulation [Figure 11]b and [Video 12]. A single outlet with atresia of one semilunar valve includes a single pulmonary trunk with aortic atresia or a single aortic trunk with pulmonary atresia.
Figure 12: Abnormalities of ventriculoarterial connection. CAT: Common arterial trunk; ccTGA: congenitally corrected transposition of great arteries; DORV: Double outlet right ventricle; HRHS: Hypoplastic right heart syndrome; HLHS: Hypoplastic left heart syndrome, LV: Left ventricle, RV: Right ventricle, TGA: Transposition of great arteries
In normal hearts, the pulmonary trunk is connected to the RV, whereas the aorta arises from the LV and gives rise to the coronary arteries and brachiocephalic vessels.
Although commonly thought to represent the spatial relationship of the aorta and the pulmonary trunk, in reality, the analysis is to clarify spatial relationships between the aortic and pulmonary valves [Figure 13] and [Figure 14] and [Video 4]. However, since the relationship of the proximal-most part of the arterial trunk is the same as the relationship of the valves, these are commonly used interchangeably. The relationship of semilunar valves is generally a reflection of VA connection although there are many exceptions to this rule.
Figure 13: Possible variations in the relationship of the great arteries. The Ao to the right and posterior to the MPA is the only arrangement labeled as normally great vessel relationship (circles with solid outline). All other arrangements indicate the malposition of great arteries. MPA: Main pulmonary artery, Ao: Aorta
Figure 14: Trans-thoracic echocardiogram in suprasternal long-axis view with the marker of the echo probe pointing toward the left shoulder showing left aortic arch and its branches. Note the reducing caliber of neck vessels with the first branch, the RBCA containing right subclavian and right carotid artery, being the widest, and the LSCA being the narrowest. The arch sidedness is assessed by the branching pattern of neck vessels. Other than a few exceptions, the first branch from the aortic arch contains contralateral carotid artery. A well-visualized aortic arch with the probe marker pointing toward the left and right shoulders identifies the left and right-sided aortic arch, respectively. DTA: Descending thoracic aorta, LCCA: Left common carotid artery, RPA: Right pulmonary artery, RBCA: Right brachiocephalic artery, LSCA: Left subclavian artery
In the earlier version of the sequential analysis, the relationship of the arterial trunks was depicted as “D” or “L” to indicate the right or left position of the aorta relative to the pulmonary trunk. This notation, however, lacks crucial information about relationships in the anteroposterior direction. Therefore, it is better to provide a detailed description.
The term “normally related great arteries” is used when the aortic valve is located to the right and posteriorly relative to the pulmonary valve. Any other relationship of the semilunar valves is malposition of great arteries [Figure 13]. The malposition is not the same as TGA. While malposition only depicts an abnormal spatial relationship of semilunar valves and arterial trunk, TGA is a type of discordant VA connection in which the aorta arises from the RV and pulmonary trunk arises from the LV [Figure 11]a and [Video 11].
The attention is then shifted to the aortic arch, its sidedness, and its branching pattern. The aortic arch is left sided if it courses over the left bronchus. In children, this assessment can be made by sweeping the probe in the left-to-right direction to assess the relationship with the trachea. This, however, is difficult to visualize in older children and adults. In such cases, the arch sidedness is assessed by analyzing the probe orientation that permits the best visualization of the arch. A well-visualized aortic arch when the probe marker is pointed toward the left shoulder indicates the left arch [Figure 14] and [Video 13]. In contrast, the right arch is better visualized when the probe marker points toward the right shoulder. The pattern of the neck vessels also provides important clues. Except in the presence of isolated carotid or brachiocephalic artery, the first branch contains a carotid artery opposite to the side of the aortic arch. In the setting of the left aortic arch, the first vessel is the right brachiocephalic artery, whereas in cases with the right aortic arch, the first branch is the left brachiocephalic artery.
Defects and anomalies
Once the three main cardiac segments and the two connecting segments have been evaluated and categorized, all associated cardiac malformations are systematically examined and described. The description can be either in the order of hemodynamic significance or an anatomic order related to the location of the abnormality within the heart.
Tips for Echocardiography in a Patient Suspected to Have Congenital Heart Disease
Most of the cardiologists and echocardiographers dealing with children are familiar with this step-by-step sequential approach to cardiac morphology. Typically, unlike adult echocardiography, which starts with a parasternal long-axis view, the echocardiography for suspected CHD starts with a subcostal view for determination of the thoraco-abdominal and atrial situs.
Some modifications in the echocardiographic approach are extremely useful while evaluating suspected CHD. The assessment of all cardiac segments is greatly enhanced using the “sweep” technique in which, depending upon views, the echo probe is moved slowly from right to left or anterior to posterior to create a series of images in a particular view. Fundamentally, the technique is the same as that used in assessing LV in the parasternal short-axis view but is much more detailed in the setting of CHD. This sweeping of echo probe permits a detailed assessment of cardiac chambers and their connections.
Once the cardiac segments have been identified and the connections have been described, then associated anomalies are assessed and described using the same systematic approach. The sequential segmental approach can be further condensed to a 10-step analysis [Table 1].
Table 1: Summary of steps for sequential segmental analysis of cardiac anatomy
The sequential segmental approach includes the use of multiple echocardiographic views and other imaging modalities for systematic evaluation of cardiac anatomy. This stepwise approach permits accurate detection of all morphologic aspects relevant for managing a patient with suspected CHD.
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