Images'in'cardiology'

Double'outlet'right''with'three' atrioventricular'valves' ! Hatem!Hosny,!Sherien!AbdelSalam,!Hossam!Wally!&!Magdi!Yacoub*! ' Aswan''Centre,'Aswan,'Egypt'

*'[email protected]' ' Abstract' The'atrioventricular'(AV)'valves'are'complex'anatomical'structures,'which' perform'sophisticated'functions'(1).''A'wide'spectrum'of'malformation'of'these' valves'can'occur'in'patients'with'AV'septal'defects.' ' We'here'describe'the'anatomical'and'functional'abnormalities'of'a'rare'form'of' the'disease,'in'which'two'valves'connect'the'right'atrium'to'both'the'right'and' left'ventricles.''There'was'no'evidence'of'regurgitation'or'cyanosis'in'the'patient,' despite'the'relatively'large'communication'between'right'atrium'and'left' .''This'patient'was'also'found'to'have'severe'subHaortic'stenosis.' ' The'pathophysiology,'haemodynamics'and'method'of'repair'for'this'condition' are'discussed'below.'

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Patient'and'methods' A'12HyearHold'female'patient'presented'with'dyspnea'on'moderate'effort.''She' had'no'history'of'cyanosis,'and'her'resting'oxygen'saturation'was'98%.'' Echocardiography'revealed'an'atrioventricular'septal'defect'(AVSD),'with'a' closed'atrial'component'and'an'almost'closed'ventricular'component,'with'what' appeared'to'be'aneurysmal'tissue'containing'a'minor'leak'(Figures'1'and'2).''A' cord'could'be'seen'attached'to'that'aneurysmal'tissue'(Figure'3),'and'there'was' mild'regurgitation'through'the'“cleft”'left'AV'valve.''The'patient'also'had'a'subH aortic'membrane'with'a'peak'gradient'of'70'mmHg'across'the'left'ventricular' outflow'tract,'mild'aortic'regurgitation'and'left'ventricular'hypertrophy.''There' was'no'right'or'left'ventricular'dilatation.''' ' The'patient'was'referred'to'surgery'for'resection'of'the'subHaortic'membrane,' and'repair'of'the'left'AV'valve.''In'surgery,'the'right'atrium'was'opened'for'transH septal'access'to'the'left'AV'valve.''On'opening'the'right'atrium,'two'AV'valves' were'found:'a'right'AV'valve,'directly'attached'to'the'muscular'interHventricular' septum'and'opening'to'the'right'ventricle,'with'no'ventricular'septal'defect'or' aneurysmal'tissue;'and'another'small'orifice'opening'to'the'left'ventricle'(Figure' 4).''There'was'no'atrial'septal'defect,'but'the'atrial'septum'was'incised'at'the' 'ovalis.''Through'here'the'left'AV'valve'was'observed'opening'to'the'left' ventricle'with'a'cleft'(a'zone'of'apposition'between'the'bridging'leaflets).' ' We'believe'that'this'patient'had'an'AVSD'with'a'totally'closed'ventricular' component,'a'double'orifice'left'AV'valve'and'a'totally'closed'atrial'component.'' She'also'had'a'malaligned'interHatrial'septum,'which'instead'of'separating'the' right'and'left'AV'valves,'separated'the'two'orifices'in'the'left'AV'valve,'keeping' the'smaller'accessory'orifice'in'the'right'atrium'and'thus'forming'a'double'outlet' right'atrium.' ' During'the'operation,'the'fossa'ovalis'was'excised,'creating'good'communication,' and'the'cleft'in'the'bigger'orifice'was'closed.''After'this,'a'fresh'autologous' pericardial'patch'was'used'to'separate'the'right'AV'valve'from'the'smaller'orifice' in'the'left'AV'valve'(Figure'5).''The'patch'was'also'used'to'separate'the'right'and' left'atria,'leaving'the'small'orifice'connected'to'the'left'atrium'(Figure'6).''The' coronary'sinus'was'left'in'the'left'atrium'to'avoid'making'a'“waist”'between'the' two'left'AV'valve'orifices.''The'subHaortic'membrane'was'resected'with'a'small' myectomy,'performed'through'a'transHaortic'approach.' '

Discussion' This'patient'demonstrated'several'features'of'a'rare'variant'of'AV'septal'defect,' where'3'AV'valve'orifices'are'present.''The'smaller'left'AV'valve'orifice' communicated'from'the'right'atrium'to'the'left'ventricle,'and'the'tiny'systolic' flow'recorded'was'trivial'regurgitation'through'that'orifice'(Figure'2).' ' The'lack'of'cyanosis'and'normal'resting'oxygen'saturation'(98%)'can'be' explained'by'the'fact'that'the''preferentially'flowed'from'the'right'atrium' to'the'right'ventricle,'because'the'right'AV'valve'was'significantly'bigger'than'the' small'accessory'orifice.''In'addition,'left'ventricular'compliance'was'much'less' than'that'of'the'right'ventricle,'and'further'decreased'because'of'the'left' ventricular'hypertrophy,'caused'by'the'subHaortic'membrane.''This'is'clearly' visible'by'colour'Doppler'in'the'preHoperative'echo'(Figure'1).''The'image'shows' almost'no'forward'flow'from'the'right'atrium'to'left'ventricle'across'the' accessory'orifice.''This'is'contrasted'with'the'postHoperative'echo'(Figure'7),' showing'good'flow'across'both'the'left'AV'valve'orifices.' ' A'decision'was'made'to'reconnect'the'accessory'orifice'to'the'left'atrium'rather' than'just'closing'it,'because'the'other'left'AV'valve'orifice'alone'was'judged'as' being'too'small'for'the'patient’s'body'size,'particularly'after'closure'of'the'cleft.' ' A'double'orifice'left'AV'valve'occurs'in'AVSD'when'a'tongue'of'tissue'extends' between'the'mural'leaflet'and'one'of'the'LV'components'of'the'bridging'leaflets' (2).''It'occurs'in'around'5%'of'patients'with'AVSD'(3).''Surgical'repair'of'the'left' AV'valve'involves'closure'of'the'cleft'in'the'main'orifice,'whilst'leaving'the' accessory'orifice'intact.''Bridging'tissue'should'not'be'divided,'as'it'is'crucial'for' valve'function'(4).' ' Rarely,'AVSD'can'occur'without'interHatrial'or'interHventricular'communication' (5).''The'hallmark'for'diagnosis'in'such'cases'is'the'presence'of'a'common'AV' junction,'with'a'triHleaflet'left'AV'valve.''There'are'however'few'reports' describing'a'double'outlet'right'atrium'caused'by'malHaligned'atrial'or' ventricular'septae'(6).' ' The'patient'described'in'this'report'demonstrated'a'unique'combination'of'the' rare'occurrences'of'AVSD,'with'a'double'orifice'left'AV'valve,'intact'septae'and'a' double'outlet'right'atrium,'in'addition'to'the'subHaortic'membrane.' ' ' ' ' ' ' ' ' ' Figure'1:'Pre=operative!trans=oesophageal!echocardiography,!showing!the! diastolic!flow!across!the!atrioventricular!valves,!with!almost!no!diastolic!flow! across!the!accessory!orifice!(arrow).! ! ' '

' Figure'2:'Pre=operative!trans=oesophageal!echocardiography,!showing!the!systolic! “leak”!through!the!accessory!orifice!(arrow).! ! ' ' ' Figure'3:'Pre=operative!trans=oesophageal!echocardiography,!showing!a!cord! attached!to!the!accessory!orifice!(arrow).! ' ' ' ' Figure'4:'Intra=operative!surgeon!view,!through!the!opened!right!atrium,!showing! the!normal!sized!right!AV!valve!(arrow)!opening!to!the!right!ventricle,!in!addition! to!the!smaller!orifice!through!which!the!suction!pump!tip!is!passing!to!the!left! ventricle.! ! '

! ! Figure'5:'Intra=operative!surgeon!view,!through!the!opened!right!atrium,!after! excision!of!the!fossa!ovalis,!showing!the!small!accessory!atrioventricular!valve! orifice!(red!arrow)!separated!from!the!right!AV!valve!(not!shown)!by!the! pericardial!patch!(yellow!arrow).!!The!suction!tip!is!passing!through!the!created! atrial!septal!defect,!to!the!larger!left!AV!valve!orifice.!!The!blue!arrow!points!to!the! coronary!sinus!ostium.! ! ! ! ! Figure'6:'Pre=operative!trans=oesophageal!echocardiography,!showing!the! unobstructed!communication!of!the!left!atrium!to!the!two!left!atrioventricular! valve!orifices!(blue!arrows).!!The!red!arrow!shows!the!created!atrial!septal!defect! and!the!yellow!arrow!points!to!the!pericardial!patch.! ! ! ! ! ! ! Figure'7:'Post=operative!trans=oesophageal!echocardiography,!showing!the! diastolic!flow!across!the!two!left!atrioventricular!valve!orifices.!

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2.'' Anderson'RH,'Spicer'D.'Anatomy'of'Common'Atrioventricular'Junction'With' Complex'Associated'Lesions.'World!Journal!for!Pediatric!and!Congenital!Heart! Surgery.'2010;1(1):112H118.'doi:10.1177/2150135110361362.'

3.'' Warnes'C,'Somerville'J.'Double'mitral'valve'orifice'in'atrioventricular'defects.'Br! Heart!J.'1983;49(1):59H64.'doi:10.1136/hrt.49.1.59.'

4.'' Hosny'H,'AbdelSalam'S,'Mohsen'T,'Afifi'A.'Double'orifice'left'AV'valve'with'partial' atrioHventricular'septal'defect.'Aswan!Heart!Centre!Science!&!Practice!Series.' 2011;2011(2):18.'doi:10.5339/ahcsps.2011.18.'

5.'' Kaski'JP,'Wolfenden'J,'Josen'M,'Daubeney'PEF,'Shinebourne'EA.'Can'atrioventricular' septal'defects'exist'with'intact'septal'structures?'Heart.'2006;92(6):832H835.' doi:10.1136/hrt.2005.069278.'

6.'' Edwin'F,'Kinsley'RH,'Mamorare'HM,'Govendrageloo'K.'The'spectrum'of'doubleH outlet'right'atrium'including''with'three'atrioventricular'valves.'Eur!J! Cardiothorac!Surg.'2012;41(4):947H949.'doi:10.1093/ejcts/ezr073.'

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