ECHOCARDIOGRAPHY OF CONGENETAL LV AND RV INFLOW ANOMALIES

Dr G.RAGHU KISHORE

INTRODUCTION

• Congenital anomalies of the mitral valve represent a wide spectrum of lesions thatare often associated with other congenital heart anomalies.

• In a study by Banerjee A, Kohl T, Silverman NH et al (Am J Cardiol 1995;76:1284—91) congenital malformations of the mitral valve were detected in almost 0.5% ofthe 13,400 subjects.

• These lesions can have a variable impact on valve function. When necessary,surgical repair provides good long-term results.

• Although mitral valve replacement appears to provide acceptable mid- and long-term results , mitral valve repair is always preferable when possible.

• Because suboptimal primary repair is a significant predictor forreoperation, the successful management of congenital mitral valvedisease is closely dependent on the preoperative assessment of theanatomical substrate.

• An accurate description of the malformations can be achievedthrough echocardiography but requires prior knowledge of theselesions.

• the mitral valve should be analysed as an entire complex, includingthe valvular leaflets, tensor apparatus and papillary muscles.

Anatomy of mitral valve

Mitral valve apparatus :-

Mitral valve Annulus.

Mitral leaflets with commissures.

Chordae tendinae.

Papillary muscles.

Supporting LV Wall.

Altogether called as mitral valve complex.

Resembles the Bishops “mitre” .

Mitral valve Annulus

Annulus :- fibroelastic ring. Encircles the valve orifice in cone like manner.

Annulus is elliptical in shape in systole & circular in diastole.

Normal mitral anatomy. (A) Schematic representation of the saddle-shaped mitral annulus. (B) Anatomical photograph of anormal mitral complex with its two papillary muscles connected to the leaflets by chordae tendinae. The aortic valve is in direct continuitywith the anterior leaflet of the mitral valve. (C) Photograph of a normal mitral valve seen from the left atrium (as seen by a surgeon). (D)

Both leaflets are divided into three scallops according to the classification by Carpentier et al.. LV: left ventricle; PM: papillary muscle.

Mitral leaflets & commissures

AML :- Anterior mitral leaflet.

triangular in shape.

Is in continuity of aortic annulus.

Encircles on 1/3rd of annulus, but covers 2/3rd of valve orifice area.

PML :- posterior mitral leaflet.

Quadrangular in shape.

Occupies 2/3rd of the annulus, but covers only 1/3rd of the valve area.

Carpentiers nomenclature

Anterior leaflet is termed as “A”.

A1 scallop:- lateral third.

A2 scallop:- middle third.

A3 scallop:- medial third.

Posterior leaflet is termed as “P”.

P1 scallop:- lateral third.

P2 scallop:- middle third.

P3 scallop:- medial third.

Chordae tendinae

These are fine fibrous strings radiating from the papillary muscles and attach to corresponding halves of the anterior and posterior mitral leaflets.

Chordae arising from the APM, attach to lateral half of A2,A1,AC,P1,lateral half of P2.

Chordae arising from PPM, attach to medial half of A2, A3, PC, P3, medial half of P2.

Papillary Muscles

Located at the junction of the apical (lower) third & middle third of the left ventricle.

2 in number.

APM :- antero-lateral wall of LV.

PPM :- postero-medial wall of LV.

APM :- has dual blood supply.

- OM of LCX.

- D1 of LAD.

PPM:- has single blood supply.

- Last OM/ RCA.

(A) Echocardiographic parasternal long-axis view showing a normal mitral complex(B) Echocardiographic parasternal short-axis view showing the normal position of the papillary muscles

(C) Three-dimensional echocardiography of a normal mitral valve.

The major axis (inter commissural diameter) of the

mitral annulus is found at a bicommissural 2-chamber TTE view (when P1-A2-P3 mitral

leaflet scallops are visualized) or a mid-oesophageal bi

commissural view at 45-60°during TEE

minor axis (antero-posterior diameter) of the mitral

annulus can be performed at end-systole during TTE in the

apical long axis view (3-chamber view) or its TEE equivalent, found at mid-

oesophageal level with 135°tilt of the probe

Congenital anomalies of the mitral valve

• Mitral leaflets Mitral valve prolapse (MVP)Isolated cleft mitral valve (ICMV)Double orifice mital valve (DOMV) Mitral RingCongenital MSEbstein’s malformation of the mitral valve

• Tensor apparatus Arcade or hammock valveStraddling mital valve

• Papillary muscles Parachute mitral valve

Isolated cleft(ICMV)

• Isolated cleft of the anterior mitral valve leaflet is a rare but well-known finding the origin of which is under debate.

• some authors have considered isolated cleft to be a ‘forme fruste’ ofAVSD whereas others have supposed it to be a distinct morphologicalentity.

• The definition of a mitral cleft is a division of one of the leaflets(usually the anterior leaflet) of the mitral valve.

• This must not be mistaken with the so-called ‘cleft’ in AVSD

ICMV• On transthoracic echocardiography, it looks like a slit-like hole in the anterior mitral

leaflet.

• Chordal attachments may connect the edges of the cleft to the ventricular septumand subsequently create a subaortic obstruction.

• Rarely, isolated cleft may be seen in the posterior leaflet of the mitral valve.

• Although it may occur at any segment of the posterior leaflet, the predominantlocalization of the cleft is within scallop P2.

• Cleft of the posterior mitral leaflet has been reported in association withcounterclockwise malrotation of the papillary muscles that may, again, lead one tosuspect a common embryological origin with AVSD

Echocardiographic comparison of isolated anterior mitral cleft and isolated posterior mitral cleft. (A) 2D echocardiographicapical four-chamber view showing the eccentric mitral regurgitation of an isolated anterior mitral cleft. The regurgitation jet ispassing along the lateral wall of the left atrium. Parasternal short-axis view showing (B) mitral regurgitation in colour Dopplermode and(C) the cleft, which looks like a slit-like hole, pointing toward the aortic root (white arrow). (D) 2D echocardiographicapical four-chamber view showing the eccentric mitral regurgitation of an isolated posterior mitral cleft. The regurgitation jetis passing along the atrial septum. (E and F) Three-dimensional echocardiographic views of the posterior mitral cleftseparating the posterior leaflet into two equal parts

2D Echo - ICMV

• Visualization of the cleft attachments is best from a subxiphoid short-axisview.

• ICMV with an abnormal conotruncus has more vertically positioned cleftattachments near the LV outflow.

• Examination of ICMV is focused on determining if outflow tractobstruction(aortic or pulmonary) by cleft

• best accomplished from modified subxiphoid windows that profile eachrespective structure of interest.

• One often needs to rotate the transducer from standard long- and short-axisviews to visualize these pathways better

Systolic frame from a modified short-axis view obtainedfrom a subxiphoid window profiling an isolated cleft ofthe mitral valve in a young child. From the subxiphoidwindow the chordae of the cleft (white arrow )areperpendicular to the plane of interrogation, whichprovides better visualization compared with theparasternal short-axis window.

Diastolic frame from a modified view obtained from asubxiphoid window profiling an isolated cleft of themitral valve (ICMV) in an infant with D-transposition ofthe great arteries {S,D,D}. Note the vertical orientation(arrow) of the cleft attachments, typical for ICMV withtransposition or double-outlet right ventricle (see text).The cleft attaches to the leftward aspect of the leftventricular outflow.

ICMV vs AVCD

• Kohl et al. clearly demonstrated that in AVSD, the positions of bothpapillary muscles were rotated counterclockwise , whereas in isolatedcleft, the position of the papillary muscles was similar to that innormal children.

• In AVSD, the posteromedial papillary muscle is more rotated than theanterolateral one, making it a good marker of this lesion.

• In AVSD, the cleft points towards the ventricular inlet septum,whereas in isolated cleft, it is usually more directed towards the aorticroot

Spatial orientation of the cleft of atrioventricular septal defect and of the isolated cleft. (A) Photograph of an atrioventricularseptal defect. Papillary muscles are horizontalized due to a counterclockwise rotation. Because the common atrioventricularvalve is bridging over the inlet ventricular septal defect, the cleft (white star) is pointing towards the ventricular septum. (B)Three-dimensional echocardiography of an atrioventricular septal defect showing cleft orientation towards the ventricularseptum (black arrow). (C) Photograph of an isolated cleft of the anterior leaflet of the mitral valve. The cleft (white star) ispointing towards the left ventricular outflow tract. (D) Three-dimensional echocardiography of an isolated anterior cleftshowing its orientation (white arrow).

Subxiphoid short-axis sweep showing isolated cleft of the mitral valve anterior leaflet. Note thehorizontal orientation of the cleft attachments in this patient with normally related great arteries.

Parasternal short-axis plane demonstrating cleft attachments to the rightward aspect of theLVOT - typical for ICMV with normally related great arteries

Modified view obtained from a subxiphoid window profiling an isolated cleft of the mitralvalve (ICMV) in an infant with D-transposition of the great arteries {S,D,D}. Note the verticalorientation of the cleft attachments, typical for ICMV with transposition or double-outletright ventricle. The cleft attaches to the leftward aspect of the left ventricular outflow.

Double orifice mitral valve(DOMV)

• DOMV is defined as a single fibrous annulus with two orifices opening into the leftventricle

• occurring in 1% of autopsied cases of CHD and is rarely isolated

• usually an ancillary finding in the setting of a more complex CHDs.

• Usually found in association with AVSD (52%), obstructive left-sided lesions (41%)and cyanotic heart disease.

• Several cases of DOMV were also reported in association with non-compaction ofthe left ventricle

DOMV- CLASSIFICATION

Trowitzsch et al. classified DOMV into three types

1) Incomplete bridge type - a small strand of tissue

connecting the anterior and posterior leaflets at the leaflet edge level

2) Complete bridge type - a fibrous bridge divides the

atrioventricular orifice completely from the leaflet edge all the waythrough the valve annulus

3) Hole type (eccentric) - a secondary orifice with subvalvular

apparatus occurs in the lateral commissure of the mitral valve.

2D Echo -DOMV

• clinical presentation is variable, mainly depending on the associatedcardiac lesion.

• MR in 43% of cases, MS in 13% and both MR & MS 6.5%,no functionalconsequence of DOMV in 37% of cases.

• The two distinct orifices are clearly recognized in parasternal short-axis view

• DOMV opens as two circles in diastole rather than a single ellipsoidmitral orifice

The key to the echocardiographic diagnosis of DOMV is the visualization of twoanterograde flows through the mitral valve

• Cross-sectional views may be performed from the apex towards the base of the heart,in order to differentiate the three types of DOMV.

• The orifices of the ‘complete bridge type’ are seen throughout the scan, while in the‘incomplete bridge type’, the orifices are seen only at the level of the papillarymuscles. In the ‘hole type’, the smaller (accessory) orifice is seen at about themidleaflet level.

• 3D echocardiography is efficient for accurately depicting DOMV, even in the newborn

Double orifice mitral valve. (A) Photograph of a double orifice mitral valve seen by the left atrium (as seen by asurgeon), with a single fibrous orifice and (B) a double orifice mitral valve associated with partialatrioventricular septal defect seen by the left ventricle. (C, D) 2D and 3D echocardiographic parasternal short-axis views showing the two distinct orifices. (E) Apical 4C Doppler colour view showing two typical anterogradeflows (arrows) through the mitral valve.

A parasternal short-axis plane demonstrating a double-orifice mitral valve. Note the equal size ofeach orifice and their location above their respective papillary muscle groups.

A short-axis plane in a fetus of 31 weeks’ gestation demonstrating a double-orifice mitral valve

Mitral ring

• Also called supravalvar mitral ring or supramitral ring

• One of the components described by Shone et al. in Shone’s syndrome(association of coarctation of the aorta, subaortic stenosis, PMV andsupramitral ring)

• Exceptionally isolated, this lesion is more often associated withvarious other anomalies of the heart mainly VSDs and left-sidedobstructive lesions.

Mitral Ring

• Two types

1) The supramitral ring is a fibrous membrane originating just abovethe mitral annulus, beneath the orifice of the LAA, within themuscular atrial vestibule, not adhering to the leaflets and associatedwith a normal subvalvular apparatus.

2) The intramitral ring is a thin membrane located within the funnelcreated by the leaflets of the mitral valve, closely adherent to thevalve leaflets ,always combined with abnormal subvalvular apparatus.

Mitral Ring

• Must be distinguished from cor triatriatum sinister ,a fibromuscular membrane,clearly separated from the mitral valve (proximal to the left atrial appendage) thatdivides the left atrium into two parts.

• The ring can be either complete, circumferential or partial

• It creates a stenosis that is usually progressive with a median age at diagnosis of 36months in the largest published series

• TTE accurately detects the mitral ring in up to 70% of cases.

• Postoperative outcome is better for supramitral ring, with no need for reoperationafter the ring excision, compared with frequent recurrence (50%) in case ofintramitral ring

Mitral ring. (A) Photograph showing a supramitral ring (arrows) seen from the left atrium. The membrane is originating just above the mitral annulus,beneath the orifice of the left atrial appendage. (B) 2D 0echocardiographic PLAX view showing an intramitral ring (arrows) located within the funnelcreated by the mitral leaflets and (C) Doppler colour mode showing blood flow acceleration that begins at the insertion of the membrane. (D)Transmitral pulsed Doppler acquisition showing mitral stenosis. (E) 3D echocardiographic PLAX view showing the same intramitral ring (arrows). (F)Three-dimensional view from the left atrium

Apical window demonstrating congenital mitral stenosis and a supravalvar mitral ring (SVMR). Note the prominentpapillary muscle that extends further toward the annulus than in a normal apparatus, the accompanying shortenedchordae and hypoplasia of the annulus. The membranous SVMR is seen as a thin projection from the atrial side ofthe leaflet, extending from the annulus into the supravalvar flow orifice. Color Doppler in the same imaging planedemonstrating flow acceleration beginning just prior to the annulus – a characteristic finding in SVMR, which ifpresent should prompt the imager to undertake an extensive search for an unrecognized SVMR. Note theadditional egress from the inflow directed medially via an abnormal intrachordal space. This type of complex infloworifice makes accurate measurement of the flow orifice area particularly challenging

Systolic frame from a TEE, mid-esophageal four-chamber view

Note the enhanced visualization of the supravalvar mitral ringprovided by TEE. The

membrane is conspicuous, extending from both

the lateral aspect of the atrialside of the leaflet and the medial

aspect (arrow).

Congenital Mitral Stenosis

• Congenital mitral stenosis (MS) is defined as an abnormality at anylevel of the mitral valve apparatus that results in restriction ofdiastolic filling.

• Worldwide, the prevalence of acquired rheumatic mitral stenosisexceeds that of congenital MS; however, in developed nationscongenital MS is more common.

• congenital MS typically involves disruption of several components ofthe valve apparatus, hypoplasia of additional leftsided structures andother complex cardiac lesions, which makes the determination ofspecific etiology equally challenging.

• Four common anatomic subtypes:

- typical congenital MS

- parachute MV

- supravalvar mitral ring

- hypoplastic MS.

• By limiting flow to distal structures during embryologic development,MS may play a role in the hypoplasia or stenosis of downstreamstructures

• Typical congenital MS involves thickened and rolled leaflets,shortened chordae tendineae with absence of the interchordalspaces, and underdeveloped papillary muscles, which may be closelyspaced.

• Typical MS has also been termed “symmetric” , implying equaldistribution of chordae to each papillary muscle and equal papillarymuscle size.

• Asymmetric papillary muscle location, size and distribution ofchordal attachments is common found in approximately 30%nd inthe extreme results in a true parachute MV with all chordaeinserting into a single papillary muscle – typically the anterolateralpapillary muscle is absent

• Congenital MS is strongly associated with obstructive leftsidedlesions including PV stenosis, supravalvar and valvar AS, PMV, SVMR,subaortic membrane and CoA – the last four lesions together wereoriginally described by Shone et al.

• Congenetal MS is best imaged in the apical and ventricular long- andshort-axis planes.

• The subxiphoid window in infants and younger children typically givesa higher yield than the parasternal window.

• Slow, targeted sweeps of the mitral apparatus utilizing magnificationmode provide optimal visualization to differentiate subtypes of mitralstenosis

A late-systolic frame in typical congenitalmitral stenosis from an apical 4C- view.Note the thickened and short chordae

An early diastolic frame – note the rolled andthickened leaflet tips, the reduced orifice sizeand doming of the middle aspect of theanterior leaflet A

Typical congenital mitral stenosis from an apical 4-chamber view. Note the thickened and shortchordae, the rolled and thickened leaflet tips, the reduced orifice size and the diastolic domingof the middle aspect of the anterior leaflet.

Color Doppler of typical congenital mitral stenosis from an apical 4-chamber view. Note theflow acceleration in the distal aspect of the inflow with the proximal isovelocity surface area(PISA) aliased lines representing increasing velocity “shells” as the flow approaches the smallorifice

A short-axis plane from a subxiphoid window in typical congenital mitral stenosis. Well-spaced papillarymuscle groups are readily appreciated in this short-axis plane – excluding parachute mitral valvemorphology. Note that the orifice appears falsely adequate in the short-axis view, due to the relationshipof the distal aspect of the leaflets to the orifice – the leaflet adjacent to the orifice runs nearly parallel tothe orifice. This aspect of the anatomy is only appreciated in orthogonal views (apical 4-chamber)

Ebstein’s malformation of the mitral valve

• Ebstein’s malformation of the left-sided atrioventricular valve has been reported in rarecases of corrected transposition of the great arteries

• involved valve was obviously of tricuspid morphology.

• The first case of Ebstein’s malformation of a morphological mitral valve was described in1976 by Ruschhaupt et al.

• The malformation exclusively affects the posterior valve leaflet, which is plastered intothe left ventricle wall, thus displacing the mitral valve orifice downward into the leftventricle.

• Unlike Ebstein’s malformation of the tricuspid valve, the atrialized inlet portion is usuallynot thinned.

• This exceedingly rare anatomical condition causes mitral insufficiency

Anomalies of the tensor apparatus

Arcade or hammock valve

• A direct connection of the papillary muscles to the mitral leaflets, eitherdirectly or through the interposition of unusually short chordae.

• Sometimes called hammock valve because it mimics a hammock when thevalve is observed from an atrial aspect (as seen by a surgeon).

• The tendinous cords are thickened and extremely short, reducing theintercordal spaces and leading to an abnormal excursion of the leaflets thatmay cause both stenosis and insufficiency.

• When the space between the abnormal chordae is completely obliterated, afibrous (muscular) bridge (band) joins the two papillary muscles.

Arcade or hammock valve

• In the most severe form, with no chordae tendinae at all, the papillary muscles aredirectly fused with the free edge of the leaflet

• It may be seen in association with PMV.

• Believed to be the result of an arrest in the developmental stage of the mitral valvebefore attenuation and lengthening of the collagenized chordae tendinae

• Echocardiographical appearance shows the short chordae and restricted motion ofthe leaflets with limited coaptation but also, in Doppler colour mode, multiple jetsthrough the reduced interchordal spaces

Arcade/hammock mitral valve. (A) Photograph showing the typical aspect of a hammock mitral valve seen from the left atrium and (B) the same valveseen from the left ventricle. (C and D) Postmortem specimens of anomalous mitral arcade characterized by fused interchordal spaces (arrows). (E) 2D-echocardiographic view showing the obliterated interchordal spaces (arrow). (F) The typical aspect in Doppler colour mode of multiple jets through thereduced interchordal spaces.

Straddling mitral valve

• SMV is defined by an abnormal attachment of the mitral chordae to both ventricles.

• Always associated with a ventricular septal defect

• According to this definition, an AVSD nearly always straddles but the term‘straddling’ can only be applied to true mitral or tricuspid valves.

• The mitral valve always straddles through a conoventricular (misalignment) type ofVSD.

• SMV is almost always associated with conotruncal anomalies like DORV or TGA

• SMV must be distinguished from the overriding of the mitral valve, which qualifies amitral annulus committed to the two ventricular chambers. In that case, the mitralvalve is shared between the ventricles

Straddling mitral valve. (A) Photograph of a straddling mitral valve associated with a double outlet right ventricle, seen fromthe right ventricle. The mitral valve is attached to the right ventricle by chordae (white arrow) that pass through the ventricular septaldefect. (B) The same mitral valve seen from the left ventricle. (C) Echocardiographic view showing the abnormal attachment (white arrow)of the mitral valve in the right ventricle.

Modified long-axis view obtained from a subxiphoid window profiling major straddling of themitral valve in an infant with double-outlet right ventricle (DORV) {S,D,D}. Note the commissureof the straddling valve with attachments within the infundibulum and the marked degree ofstraddling that would complicate biventricular repair

A modified short-axis view obtained from a subxiphoid window profiling major straddlingof the mitral valve (SMV) in an infant with TGA {S,D,D} pulmonary stenosis. Note theinferior positioned tricuspid valve (TV) inflow and the straddling via the anterior (outflow)aspect of the ventricular septum.

Anomalies of the papillary muscles

Parachute mitral valve

• One of the common causes of congenital mitral stenosis, with incidence of 0.17%

• True PMV is characterized by unifocal attachment of the mitral valve chordae to asingle (or fused) papillary muscle.

• This single papillary muscle is usually centrally placed and receives all chordae fromboth mitral valve leaflets.

• In PLAMV, chordae are distributed unequally between two identifiable papillarymuscles, with most or all of the chordae converging on a dominant papillary muscle.

• The dominant papillary muscle, classically posteromedial, is of normal size,whereas the other is elongated and displaced higher in the ventricle with its tipreaching to the annulus.

• In both PMV and PLAMV, the chordae are short and thickened, thus restricting themotion of the leaflets.

• PMV or PLAMV are commonly seen in association with other obstructive lesionsaffecting the left heart or conotruncal anomalies

• Mitral valve should always be carefully inspected in order to diagnose PMV if anyother feature of Shone’s syndrome is present.

• Because opening of the mitral valve is limited, true PMV is highly associated withmitral stenosis. Mitral regurgitation occurs less commonly but must be equallycarefully followed because of its progressive evolution.

• In the parasternal short-axis view, a single papillary muscle isconfirmed at the mid-level of the left ventricle.

• The pathognomonic ‘pear’ shape of the mitral valve is seen in thefour-chamber view, with the left atrium forming the larger base of thepear and the mitral leaflets the apex.

• In this view, the valve has a typical ‘domed’ appearance in diastole.

Parachute mitral valve. (A) Postmortem specimen of a true parachute mitral valve showing a fused papillary muscle (star).All chordae areinserted into this single papillary muscle. (B) Photograph of a parachute-like asymmetric mitral valve. The posteromedial papillary muscle isclearly underdeveloped. (C) 2D echocardiographic PLAX view showing a single papillary muscle connected to the leaflets by short and thickenedchordae (arrow). (D) Apical 4C view showing the pathognomonic pearshaped mitral valve. (E and F) Parasternal short-axis views showing thetypical aspects of both the single papillary muscle and the mitral valve.

A subxiphoid short-axis view demonstrating a parachute mitral valve. Note the presence ofa hypoplastic anterolateral papillary muscle that receives no chordae, which is the mostcommon arrangement in the parachute lesion

Morphologic anomalies of the tricuspid valve (TV)

• Tricuspid stenosis - hypoplasia and thickening of the valveleaflets with a reduced valve orifice

• Ebstein anomaly - displacement of part of the origin of thevalve leaflets from the atrioventricular junction into the cavity of theright ventricle

• Tricuspid dysplasia - malformed but not displaced valveleaflets

• Double-orifice tricuspid valve - TV exhibiting two valveorifices

Tricuspid stenosis (TS)

• It is a condition producing obstruction to right ventricular filling due toabnormalities of the TV in respect of its form, annular dimension and/orfunction.

• Rarely, the obstruction is found at the subvalvar or supravalvar level.

• The majority of reported cases of isolated TS are sporadic.

• TS has been reported in congenital polyvalvular disease, and is associated with trisomy 13, 15 and 18.

• In the rare form of congenital isolated TS, the reduced valve orifice ismainly due to thickening of the TV leaflets and abnormal chordalattachments.

• Congenital TS associated with annular hypoplasia, as found in severalforms of congenital heart disease, is usually characterized by annularhypoplasia with abnormalities of all parts of the TV including leaflets,commissures, chordae and papillary muscles.

• Congenital supravalvular TS is caused by a membrane attached eitherat the level of the tricuspid annulus or at the midportions of theleaflets

• Isolated TS will cause diastolic obstruction of flow from the RA intothe RV.

• The increase of right atrial and central venous pressure will dependon right ventricular compliance, the effective size of the TV orifice,and the possibility of a right-to-left shunt through a PFO or an ASD.

• The pathophysiology of TS associated with other forms of congenitalheart disease, mainly right heart hypoplasia, will depend on theunderlying lesion and the size of an associated atrial septal defect.

Characterization of TS

• Thickened, rolled TV leaflets may also dome in diastole, further shorteningchordae with abnormal attachments;

• a stenosing membrane may be detected within the funnel of the TV thusrestricting the opening of the leaflets

• measurement of maximal velocity (Vmax) across TV: normal value <0.8 m/s;Vmax >1.3 m/s in absence of left-to-right shunt indicates significant TS

• calculation of maximal and mean diastolic transvalvular pressure gradient.

• Assessment of tricuspid regurgitation (TR): hemodynamic assessment of TRby spectral Doppler and color flow mapping

Parasternal long-axis right ventricular inflow demonstratingtethering of both anterior and septal tricuspid valve leaflets,annulus dilation with failure of central leaflet coaptation (arrow),and dilation of the rightatrium (note the position of the interatrialseptum) in a child after dilation of criticalpulmonary stenosis ininfancy.

Modified parasternal short-axis view of tricuspid stenosisassociated with annular hypoplasia (arrow) and a smallventricular septal defect leak.

Subcostal short-axis viewof tricuspid stenosis associatedwith annular hypoplasia andatrial septal defect. Note theprominent Eustachian valve(arrow)

Tricuspid valve dysplasia

• Tricuspid valve dysplasia is defined as a spectrum of congenitalmalformations of valve leaflets, chordae and papillary muscles.

• It frequently leads to tricuspid regurgitation.

• Reported cases of TV dysplasia are sporadic, although associationwith Down syndrome is reported

• Depending on its degree, TR associated with TV dysplasia will cause progressive dilation of the right atrium and right ventricle; it may also trigger arrhythmias.

• The spectrum of TV dysplasia ranges from minimal changes with mildly dysplastic,thickened leaflets but normal chordae and papillary muscles, through short chordaeand underdeveloped papillary muscles, to severe changes including agenesis ofentire leaflets and subvalvar structures.

• In contrast to Ebstein anomaly there is no displacement of both the septal and muralleaflets. This is important for discriminating the extreme variant of TV dysplasia –unguarded orifice TV, exhibiting only rudimentary valve tissue at the atrioventriclarjunction – from Ebstein anomaly.

• In tricuspid dysplasia, and its extreme variant, the leaflet will be absent, notdisplaced .

• In the rare case of unguarded orifice, ruling out displacement of the posteriorleaflet will confirm the diagnosis.

Apical 4-chamber view ofcolor flow mapping oftricuspid regurgitation dueto tricuspid dysplasia.

Apical 4-chamber view demonstrating tricuspid valve dysplasia. Note the normal insertion ofthe septal tricuspid leaflet at the cardiac crux and the lack of central valve leaflet coaptation.

Double-orifice tricuspid valve (DOTV)

• Double-orifice tricuspid valve (DOTV) is defined as an anomalous tricuspidvalve exhibiting two orifices. It is also termed “duplication of the TV’’

• Is an extremely rare anomaly and is reported to be associated withatrioventricular septal defect, tetralogy of Fallot and several TV anomaliessuch as Ebstein anomaly, tricuspid dysplasia, TV prolapse and straddlingTV

• The etiology of DOTV is not known.

• DOTV is considered as benign, and its pathophysiology is determined by associated lesions.

• In DOTV, 2D echocardiography can demonstrate duplication of theostium on parasternal short-axis, apical 4- chamber and parasternallong-axis views through the right ventricular inflow tract.

• Imaging of the two orifices can best be achieved from subcostal short-axis and en face views.

2D echo with subcostalshort axis view (enface view)showing double orifice ofright sided component ofthe common AV valve

Anomalies of tricuspid valve alignment

• The tricuspid valve is termed as straddling when its chordae tendineae andpapillary muscles are attached on both sides of the ventricular septum sothat the right atrium may empty into both ventricles.

• It is termed as overriding when its annulus is connected to both ventricles.

• The degree of overriding will determine whether this connection is trulybiventricular (override <50%), with two ventricles of comparable sizepresent, or whether this connection is univentricular, with one dominantand one rudimentary ventricle (override >50%)

• Straddling and overriding may coexist

• The exact incidence of straddling/overriding TV per se is not known.

• The condition of a straddling TV is of importance in univentricularhearts, but crucial in decision-making for biventricular repair as it maybe present in 3% of lesions as VSD, tetralogy of Fallot, DORV , andtransposition of the great arteries.

• Although certainly underdiagnosed in univentricular hearts, straddlingTV is a rare condition, found in only 0.71% of autopsies in the CardiacRegistry of the Children’s Hospital in Boston

• In straddling TV in biventricular hearts, there is marked malalignmentbetween the ventricular and the atrial septum.

• The right ventricular inflow tract is usually smaller than the left ventricularinflow tract.

• The nonstraddling part of the TV opens into the right ventricle, whereas thestraddling part opens into the left ventricle.

• In order to avoid surgically induced heart block, it is important to know thatthe position of the penetrating atrioventricular bundle reflects the degree ofmalalignment

• The great arteries were either normally related (42%, complicated in themajority by TOF ) or abnormally related (58%, TGA, DORV, or doubleoutletleft ventricle)

Apical 4c view of a straddling and overriding tricuspid valve (TV), mild hypoplasia of right ventricular inflowtract, and inlet VSD.

Apical 4C view of a perimembranous/inletVSD, malalignment of IAS and IVS , overriding tricuspid valve with high offsetting(arrow) and smallish RV inflow.

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