Lai Echo VSD

VSD Echocardiography (Lai12)

Ventricular Septal Anatomy

-RV side:

-inlet septum- smooth, goes inf/post fr the hinge of TV to distal septal attachments of TV paps

-trabecular septum- inf to inlet, going ant'ly, w coarse trabecs

-septal band separates separates the smooth walled outlet fr the trabec septum

-goes sup/post fr mid part of IVS and divides into the ant-sup limb which goes twd PV

and blends into the infundibulum; and post-inf limb goes along RV free wall and merges

w parietal band.

-Pulm valve is above these muscle bands, held up by the infundibulum- circumferential

muscle band below the PV and merges infly/postly with the outlet septum

-outlet septum- aka conal septum aka infundib septum

-Ao outflow tract and AoVlv are post/rightward of the outlet septum

-membranous septum- next to the ant-septal commis of TV on R; next to RCA-NCA commis on L

-inlet zone radiates post-infly

-trabecular radiates ant-infly

-outlet zone radiates ant-superiorly

-small, w 2 parts- interventricular and AV parts, separated by the septal lefalet and ant-septal commissure of TV. the AV Septum --> offset bn the septal hinges of MV and TV w RA on R and LV on L

-Conduction Tissue w AV bundle and LBBB go thru the post-inf border of the membr spt

RIGHT SIDE:

Types

Membranous:

-VSDs in the membranous septum

-aka pari/paramembranous

-"roofed" by the TV--> fibrous continuity bn TV and MV

-located bn outlet (conus) and inlet (ventric) parts of the RV so aka conoventricular

-located just beneath commis, bn the RCA and NCA cusps of Ao vlv

-often w TV xx- redundant tissue +/- tethering of ant TV leaf and fused cords, and the leaflets can

adhere to the defect--> shunting fr LV to RA directly

Muscular:

-ant, midmuscular, apical, or posterior

-may be Swiss cheese pattern...

-may be serpiginous...

Outlet:

-absent outlet septum w Subarterial VSD (conal septal, doubly committed, juxtaarterial, subpulm)

-->Ao-Pulm cusp continuity and they lie at the same level

-in this case not only is the outlet septum gone, but also the septal part of the subpulm infundib

-post rim of the VSD is muscular if it goes inf to trabec sptm or fibrous if it goes post to membr spt.

-R cor cusp of Ao vlv isn't supported, and is often prolapsed thru the defect via Venturi effect

-malaligned relative to trabec septum - usually w other xx like TOF, interrupted Ao Arch...

-outlet septum malaligned ant/left--> elevate the floor of RVOT--> subpulm obstruction

-outlet septum malaligned post/right--> lower the roof of LVOT--> subAo obstruction

Inlet:

-post and inf to septal leaflet of TV, aka AV canal type (but aren't an AVC defect...)

-some w straddling of MV or RV cords across the VSD

Goals:

[ ] location & size of defect

[ ] relation to nearby structures- TV, PV

[ ] measure defect margins- ?transcath closure

[ ] HD assessment

[ ] flow direction by color/Doppler

[ ] RV systolic P by VSD flow and TR jet & by systolic config of IVS

[ ] mean transseptal P gradient

[ ] check for HD load- LV enlargement, systolic septal flattening fr RV P OD, incr Qp

[ ] biventric fx

[ ] assoc lesions

Imaging

-SCLA sweep inf at base then sup'ly/ant to apex

-see inlet septum and both AV and interventric parts of membranous septum

-then, see trabec septum

-SCSA sweep

-see ant-post malalignment of outlet septum

-see subarterial VSDs well w Q fr LV to PV and MPA

-then as it goes Leftward, see boundry bn RV inflow sinus and outflow part

-AP4C sweep post by CS and AV vlvs then go ant'ly

-see post septum- inlet septum above and trabec below

-then se membranous septum just inf to septal leaflet of TV

-reposition medially and clockwise rotation--> see subAo outflow tract for post malalign.

-Ant malalignment VSDs can't be seen fr AP4C well usually

-if inlet VSD, straddling can be seen

-PSLA- transects Ao and LV in long axis, so you can see ant VSDs

-subarterial VSDs seen well- see defect bn sup margin of VSD and hinge of R cor cusp of Ao vlv

-check for R cor cusp prolapse into defect (subarterial or membranous VSDs)

-see post malalignment outlet VSDs w SubAo obstruction

-inf'ly see anterior muscular VSDs

-tilt transducer to TV inflow to see paramembranous VSD

-tilt transducer to PV outflow to see ant malalignment VSD

-PSSA- good to ID VSD location

-start at base:

-Membranous VSD = 9-11 o'clock

-TV aneurysmal tissue might shroud the VSD

-Ant extension (outlet) VSD goes to 11-12 'clock

-Subarterial (outlet) VSD = 12-2 o'clock (12 to the hinge of the PV)

-Ant malalignment VSDs = 11-1 o'clock, see the ant septum more ant and L than Nl, raising subpulm outflow tract floor

-sweeping down septum, see muscular VSDs

-post muscular VSDs = 7-10 o'clock

-midmuscular VSDs = 10-12 o'clock

-ant muscular VSDs = 12-2 o'clock

-inlet (AVC type) VSDs = 7-9 o'clock