Simple shunts (ASDs, VSDs, PDA) Flashcards
(24 cards)
ostium secundum ASD
ostium primum ASD
sinus venosus ASD
ostium secundum ASD - in the middle at fossa ovalis area (Ap 4ch, SC 4ch, SAX overview)
ostium primum ASD - by the AV valves (Ap 4ch, SC 4ch)
sinus venosus ASD - near SVC or IVC (bicaval view)
which ASD is the most common?
ostium secundum ASD
which ASD is associated with Trisomy 21 (Down’s)?
ostium primum ASD
(Down also associated with AVSD, cleft MV)
Unroofed CS
complete or partial unroofing of CS, so LA communicates with RA
almost always associated with PLSVC
causes dilated CS
PFO
flap that opens with RA press > LA press (sneeze, valsalva, PHT)
foramen ovale should close at birth but sometimes flap doesn’t seal
Hemodynamics of small ASD?
O2 blood flows LA to RA
Right side volume overload and dilation
Hemodynamics of big ASD?
Increase right sided pressures…
Eisenmenger’s = shunt changes direction: RA to LA
- now dO2 blood goes to body :(
Murmur that suggests VSD?
vs. PDA?
VSD: harsh holosystolic thrill (loud bc high vel, only in systole)
PDA: continuous machinery murmur (in all phases of cardiac cycle bc press Ao > pulm, high vel)
What VSD(s) are seen in each view?
PLAX
SAX at AoV
SAX at MV/basal
SAX at paps
Ap or SC 4ch
Ap or SC 5ch
PLAX - outlet/supracristal, perimembranous; muscular
SAX at AoV - outlet/supracristal; perimembranous
SAX at MV/basal - muscular; inlet
SAX at paps - muscular
Ap or SC 4ch - inlet; muscular
Ap or SC 5ch - perimembranous; muscular
Which is the most common VSD?
perimembranous
see by AoV and TV
Gerbode VSD
LV to RA communication
possible bc TV sits more apically than MV
Hemodynamics of VSD?
1st to dilate is LEFT side
- extra blood enters RVOT and goes to lungs, LA, LV = Left side dilation and PHTN
then RIGHT side dilates
- PHTN causes RV dilation and hypertrophy
How can you calculate RVSP from VSD velocity?
RVSP = LVSP (BP cuff) - 4V^2 (CW: VSD Vmax)
Describe the relationship between VSD shunt velocity and RVSP (severity of problem)
high vel L to R - normal
low vel L to R - high RVSP, but still lower than systemic
bidirectional - RVSP = systemic
Eisenmenger’s - RVSP > systemic
AVSD
Complete vs Partial/incomplete
AVSD = Atrioventricular septal defect
caused by failure of endocardial cushions to form
associated with Downs
Complete:
- primum ASD
- inlet VSD
- 1 AV valve (5 leaflet)
Partial:
- primum ASD
- cleft MV
hemodynamics of AVSD? (complete or partial)
At birth (with normal pressures): O2 blood shunts L to R
overtime… increase right side press…Eisenmenger’s…
Later: dO2 blood goes R to L - mixed blood to body
PDA defn
what views is it seen in?
Patent ductus arteriosus = connection btw DA and LPA bc failure of ductus arteriosus to close
best seen in high PSAX - red jet at edge of pants (unless Eisenmenger’s, then would be blue)
can also see in SSN - red jet by RPA
What does CW through a PDA look like?
high velocity; continuous flow that peaks at mid - end systole
Hemodynamics of PDA?
Asymptomatic
or left side volume overload and dilation
How to calculate RVSP/PAP if PDA?
RVSP = LVSP (BP from cuff) - 4V^2 (CW: PDA Vmax)
Remember, can only use TR to get RVSP and PAP if no RVOT obs, PS, or PDA…
What is Qp/Qs?
Qp/Qs is a way to quantify shunts
Qp is pulmonary SV
- CSA - meas RVOT at MS at PV annulus
- VTI - trace PW before PV
Qs is systemic SV
- CSA - meas LVOT at MS at AoV annulus
- VTI - trace PW before AoV
**measure AT annulus (not 1 cm before like usual) - Qp/Qs is different measurements package)
Qp/Qs: what are the #1 and #2 sources of error?
1: RVOT diam and CSA
What do the values mean?
Qp/Qs = 1
Qp/Qs 1-1.5
Qp/Qs >1.5
Qp/Qs < 1
Qp/Qs = 1
normal (flow through PV and AoV is same)
Qp/Qs 1-1.5
insignificant shunt
Qp/Qs >1.5
hemodynamically significant shunt (L to R, lungs get more blood)
shunt ratio starts dropping…
Qp/Qs < 1
Eisenmenger’s (shunt reverses and goes R to L)
How do you measure if it is a PDA?
Reverse the labels for Qp and Qs
Qp - meas at LVOT
Qs - meas at RVOT
