Double Outlet Right and Left Ventricle (M/A)

DORV & DOLV (MA53)

DORV

-Ranges fr VSD to TOF to TGA

-Rare - 1-1.5% of CHD

Embryology:

-Failure to achieve conotruncal inversion (rotation); and leftward shift of the conus (Ao or pulm conus)

--> DORV, w complete origin of both GA's fr the morph RV

(pictured: normal development- note how normally conotruncus moves L ward, so Ao is over LV)

-Anderson describes a range from TOF to TGA, with DORV an initial embryologic condition, while TOF is bc of L shift of the Ao conus, and TGA is bc of a L shift of the Pulm conus. These are all likely on a spectrum, stemming from a developmental/embryological pd when both GAs are fr the RV

-Manner says DORV is bc of abNl trr vlv orientation to L ant side of the heart. The abNl connection bn muscular ventric septum and cons septum--> interventricular foramen is formed at the L side of teh subAo flow path.

Path:

-Neufeld Definition: both GA and art trunks arise fr the morph RV only, and neither semilunar valve is in fibrous continuity with either AV valve. There is usually a VSD, which is the only LV outlet

- +/- Pulm vlv or sub pulm vlv stenosis

-Lev & Wilcox Definition: One complete arterial trunk and at least half of the other emerge fr RV, thus +/- mitarl-Ao or mitral-Pulm continuity. "Thus a pt w TOF or TGA might also be DORV"

-Van Praagh states that Dx should be mutually exclusive, so to DDx bn TOF and DORV, c/s it DORV if there is both a subpulm and subAo conus (thus -->ing Ao-mitral DIScontinuity). Though there is a spectrum bn TOF w subAo VSD and the Ao-mitral fibrous continuity vs. DORV w subAo VSD w/o Ao-mitral fibrous continuity. The same spectrum applies to complete TGA and DORV

-M&A focus on classifying DORV by the VSD location relative to the GA's and by the GA relationships

-AbNl AV vlvs/chordal attachments have big impact on surgery too...

GA Relationships:

-Ao R & Post- Ao vlv/trunk fr RV, posterior and to R of PA vlv/trunk

-Ao R & Lat- (side-side)- Ao is to R of PA, and semilunar vlvs are in same transverse/coronal plane

-Ao R & Ant- (d-TGA) Ao is to R and ant to PA, +/- Ao directly anterior to PA

-Ao L & Ant- (l-TGA) Ao is to the L and ant to PA, +/- Ao nearly entirely to L of PA in near side-side w Ao left

-note we don't see Ao L and post (the normal GA relationship)

VSD Position:

-SubAo: VSD is closer to Ao vlv than pulm vlv

-SubPulm: VSD is closer to Pulm Valve than Ao; occurs when VSD is above the septal limb of crista supraventricularis (aka supracristal VSD). This type of DORV = Taussig-Bing Complex.

-Doubly Committed (subAo & subPulm): VSD is very large and so related to both.

-Remote Type: VSD is distant fr both semilunar valves, +/- posterior VSD, AV defect, or muscular VSD

1) Side by Side GAs:

-SubAo VSD:

=about 1/2 of all DORV

-Ao to R of PA

-Ao outflow penetrates parietal limb of Ao conus

-VSD is post-inf, and is closer to Ao than PA

-Ao and Pulm valves are at same horizontal level

-Ao conus is to the right; it and the conus septum (bn 2 GAs) are well seen fr RV

-VSD is the only outlet fr LV.

-Ao conus is bn the Ao vlv and the ant leaf of MV

-Angio: side by side GA, Ao to R of PA

-Ao and pulm vlvs at same horiz plane

-Ao conus, conus septum, pulm conus (bilat coni) seen well in AP view

-conus separates both semilunar valves fr both AV valves (e.g.+mitral-Ao discontinuity), on lat view

-VSD below Ao conus- seen on lat view

-Subpulm VSD = Taussig-Bing Anomaly

-rare (8% DORV)

-side by side GA

-NO PS, instead very dilated PA

-VSD ant-sup (supracristal), and immediately subjacent to pulm valve

-VSD more ant than the subAo type

-this is the only outflow for LV

-thus LV Q goes direct into PA trunk

-Pulmonary Conus separates the pulm valve fr the ant leaf of the MV

-Conus septum separates Ao and PA

-it may narrow the Ao outflow tract of RV

--> subAo stenosis--> assoc interrupted Ao Arch & CoAo

-Angio- AP view: RV angiogram: GA side by side; Ao conus, conus septum, pulm conus seen well, and conus septum less prominent than in pts w side-side GA and subAo VSD

-high VSD related directly to pulm valve seen early in classic pts, w no conus bn VSD and pulm vlv

-Doubly Committed VSD (SubAo & SubPA):

-VSD is below both Ao and PA valves, in a superior position, above crista supraventricularis (usually)

-VSD is large, extends obliquely beneath both GAs

--> may have defic of conus septum (though both Ao and PA coni remain)

-Angio- can't DDx Taussig-Bing bc on lat view of RV the VSD ishigh/ant and directly next to both Ao and PA vlvs. So, you can't tell if the VSD is related to pulm valve alone (Taussig-Bing) or both vlvs.

-Remote VSD

-most commonly in the form of a CAVC defect with DORV

-assoc w spleen xx, common atrium, visceral heterotaxia

-assoc w xx of systemic and pulm veins

-if CAVC defect, it is Rastelli type C = the ant common leaflet of the AV septal defect is undivided and is NOT attached to the crest of the ventric septum.

-Remote VSD also includes isolated VSDs and post-inf VSDs that involve the inlet part of the septum, it is bn the AV vlvs

-These usually are NOT enough to route LV Q to the GAs

-Bc they are posterior VSDs, the tri vlv can block access fr the VSD to the GA

-single or multiple muscular VSDs might be seen w DORV, and are considered remote as well

-Angio:

-CAVC- classically see deformed LVOT bc of abNl insertion of the L av vlv & see a defic in IVS

-BUT bc RV origin of both GA's, the gooseneck deformity might not be seen

2) Right Anterior Aorta = d-Malposed GA

-SubAo VSD

-unusual

-VSD is ant and sup, next to & beneath the Ao valve, above the septal limb of the crista supraventric.

-Angio: RV angio: malposed GA fr RV; Lat angio: Ao conus, conus septum, pulm conus seen well

-SubPulm VSD

-10% of DORV pts

-VSD is closer to post PA trunk bc the Ao is R and ant

-BUT, it is NOT as ant/sup as w a Taussig-Bing heart (subpulm w side-side GA)

-usually at outlet part of IVS

-Angio: need lat view to see the Ao conus, conus septum, pulm conus, bc the Ao is ant to PA trunk

-subvalvar/valvar PS is common in malposed GA pts

-see subpulm VSD well on lat view of LV angiogram

-Remote VSD

-some case reports

-similar to side-side GA DORV pts

3) Left Anterior Aorta = L-Malposed GAs

-SubAo VSD

-Ao ant/left of PA trunk

-Ao conus interposed bn Ao vlv and both the VSD and MV ant leaflets (bc conus is beneath the vlv...)

-VSD is located ant/sup, so LV Q can get to Ao

-PS is common

-Angio: see VSD at both AP/lat views, see L-malposed Ao on AP view (ao ant/left)

-see VSD on RV angiogram

-PA filled mainly via the PDA (if PS)

-SubPulm VSD

-uncommon

-VSD is post-inf, usually in a perimembranous position

-bc of malposed GA's, the VSD is closer to the post PA trunk, below the pulm conus

-Angio: malposed GAs fr RV, w Ao ant and L of PA

-Ao conus, conus septum, pulm conus seen on lat view

-VSD is below pulm conus

4) Normally Related GAs (first line of above table)

-only 2 pts in 1 report showed Nly related GAs, and both had subAo VSD at post-inf location, more closely related to the Ao. +Bilat coni,

-Angio: see Ao conal septum in AP view w RV angiogram

-lat view--> Ao fr RV w Nl relationship to PA trunk, & VSD is posterior, clse to the posterior Ao

Unusual DORV Forms:

-Intact Ventricular Septum

-7 reported cases. assoc w hypoplastic LV and MV xx. MV is the only LV outlet...

-Double Chambered RV

-2 cases reported w remote VSD

-RV had accessory chamber receiving part of the TV attachments, preventing access of GA's to the VSD.

-Tricuspid Atresia

-rare. both GA fr the hypoplastic RV, w +bilat coni

-DORV w Dextrocardia & AV Discordance

-usual atria/viscera arrangement, +dextrocardia, AV discord, PS, VSD, and DORV (L sided RV)

-often subvalvular/valvular PS; VSD is subPulm,

-side-side GA w Ao ant and Left

Associated Cardiac Anomalies

-Pulmonary Stenosis

-#1 assoc xx

-70% of pts w malposed GA have PS

-rarely can have absent pulm valve (w Sx/Si ~ to absent pulm valve syndrome)

-2nd ASD

-= only LV outlet if pt has intact IVS

-LVOTO

-some pts, to some degree

-SubAo Stenosis

-3% of DORV

-bc of excess Ao/septal conus hypertrophy or if there is much conal septal malalignment

-subpulm VSD (Taussig-Bing) can --> big PA--> progressive shift of the conus septum to R/post

--> more AS bc it compresses the Ao conus against the conus septum & TV annulus

-Assoc w Interrupted Ao Arch or CoAo if enough decr Ao Q

-MV Abnormalities

-Mitral atresia, parachute MV, subvalvar mitral ring, straddling MV, cleft ant mitral leaflet w choral attachments fr edges of the cleft to the ventric septum or thru an outlet VSD into the RV

--> mild forms of mitral valve straddling w chordal attchmnt to upper ventric septum or to a pap muscle on ventric septum, usually w/o any MV dysfx

-LSVC to RA via CS or direct to LA or LAA

-Spleen anomalies and abd heterotaxia, and pulm/systemic venous connection xx if DORV+CAVC...

-LV hypoplasia varies

-usually mild if unobstructed LV inflow; more common w decr Qp, anomalous pulm vn drainage, restrictive VSD w a large ASD

Conduction System in DORV

-AV nd is in Nl posterior position, and the penetrating bundle thru central fibrous body. THe AV bundle is in the inf/post wall of the VSD, and passes beneath the crest of the ventric septum (just like w an uncomplicated VSD)

Coronary Artery Anatomy

-Types:

-Nl (most common)

-AbNl & similar to TOF

-AbNl & similar to TGA

...

Physiology:

-d/o position of VSD & GAs, and if there is PS, pulm vasc obst dz, ASD, common atrium, AVSD, SubAo AS, VSD size

-some pts have PA SaO2>systemic SaO2, some vice versa, some equal - unrelated to whe GA relationship or presence of PS, or presence os pulm vasc obst dz, or fx'ing systemic pulm art shunts (!), but rather there is a relationship to the VSD position.

VSD Position & Oxygen Saturations:

-subPulm VSD- SaO2 PA >systemic, even if +PS or PVD

-subAo VSD- SaO2 varied w 60% of theses pts SaO2 syst>PA, and rest vice versa

-PS & PVD had no consistent effect on syst or pulm art sats

-subAo & SubPulm VSD (combined)- SaO2 PA>systemic

-Remote VSDs- different sats (??)

-Intact IVS- SaO2 PA=systemic

==> CLINICALLY, you can now tell that if pt has SaO2 syst >PA, then they don't have a subPulm PS or PVD

& if SaO2 PA>systemic then you can't predict VSD location

-Pressure Relationships

-Ao fr RV, so RV must --> systemic P

-if +PS, the PA P will be decr

-of 3 pts who had mild PS in one study, they all had very high PVR

Sx/Si:

-4 groups

1) SubAo VSD & PS

-similar to TOF, w varying cyanosis d/o PS severity, and so Sx can be delayed and pt not prsent till later in infancy.

-If severe pS, then --> early cyanosis, FTT, DOE, squatting, polycythemia

-+clubbing/cyanosis, RV impulse at LSB on precordial exam, prominent systolic thrill at LUSB (PS), w gr 4-5/6 SEM w rad to lungs. S2 usually single, +/- S3 at apex

2) Subpulmonary VSD +/- PS

-similar to TGA w VSD

-often p/w cyanosis and heart failure as early infant

-if PS, then cyanosis/polycythemia worse, so present earlier w less heart failure

-if assoc CoAo, may present w early heart failure, cyanosis, decr/absent fem pulses

-sev FTT (like TGA), w pulm plethora, and freq resp infections, sev cyanosis/clubbing

-precordial bulge & RV impulse at LSB

-gr 2-3/6 high-pitched syt murmur at LUSB

-if PS, +systolic thrill w louder murmur

-S2 loud and single bc Ao is close to chest wall and no P2 w the PS

-w incr Qp, hear apical diastolic rumble

3) SubAo VSD w/o PS

-similar to pts w large VSD and phtn

-little cyanosis, but +FTT and heart failure

-incr Qp, --> freq resp infections

-overactive heart

-+/- syst thrill at LUSB (relative PS), gr 3-4 holosyst murmur at LSB

-apical diastolic rumble & S3 at apex

4) SubAo VSD w Pulm Vascular Obstructive VSD

-=pts in group 3 that are now older and have PVD; ~ to Eisenmenger syndrome

-decr Qp, less heart failure/resp infctn

-+cyanosis/clubbing

-diminished systolic murmur, loud single S2, decresc diastolic murmur of PR (= elevated pulm P)

ECG:

-RVH & RAD bc of systemic workload

-Nl LV forces if PS; BVH if very incr Qp (e.g. subpulm VSD)

-incr LV forces if restrictive VSD

-1st Degr AV Block- common

-RAE common, esp if PS

-LAE seen w incr Qp and intact atrial septum

-if CAVC defect +DORV, then see LAD, BCH, atrial enlargement, 1st AV block

CXR:

-if PS--> like TOF w mild cardiomegaly and decr pulm vasc, and absent MPA egment--> concave upper left heart border --> boot shaped heart)

-if subpulm VSD--> CXR like TGA, espec if no PS, w incr pulm vascularity and cardiomegaly

-if subAo VSD and no PS, +/-PVD --> cardiomegaly, prominent MPA, incr pulm vasc, and if PVD then see pruning of periph art vasculature

Echo:

See:

-both GA arise fr ant RV

-Mitral-semilunar valve (Ao) discontinuity

-No LVOT except for the VSD

-2/3 cases--> can see both GAs at same time arise fr RV w/o clearly seeing both valves at same time

-PSSA- see both GA fr RV - at base, see double circle appearance of GAs = parallel orientation

-PSLA- usually must be a bit more superior at L sternal edge--> see initial course of both GA

-PA can be seen going twd lungs; Ao runs more ant/sup (usually...)

-See mitral-semilunar valve discontinuity- see a dense (fibromuscular) or muscular conus...

-Check VSD position relative to GAs

-DDx subAo vs subPulm vs doubly committed on parasternals/subs,

-check for remote VSD and CAVC defect

-check Doppler for restrictive VSDs

-Check AVC xx- CAVC, ant mitral lefalet cleft, overriding or straddling L or R AV vlv

-Check ASD

-Check pulm veins