Congenital Heart Defects: ASD/VSD Flashcards
ASD most commonly occur as defects in the
septum primum within the fossa ovalis (secundum ASD)
ASD can also occur
can involve the septum secundum near SVC (sinus venosus defects-less common)
cyanotic shunt
R -> L. worse for a kid
acyanotic shunt
L->R
Blood Flow is quantitated in terms of:
PULMONARY BLOOD FLOW (Qp)
SYSTEMIC BLOOD FLOW (Qs)
This gives us a ratio of Qp/Qs This will equal 1:1 (or 1) in a normal individual
The general rule is shunts that DO NOT cause increase in right heart size
(Qp:Qs
Ostium Secundum
most common
formed by failed growth of the septum secundum or
rapid reabsorption of the septum primum
OSTIUM SECUNDUM LOCATION
mid-atrial
PFO
A patent foramen ovale (PFO) is a small channel that has little hemodynamic consequence; it is a remnant of the fetal foramen ovale.
In some cases the PFO can be larger and require treatment
PFO closure from right side
The initial inflation of the lungs causes changes:
Decreases PVR results in increased blood flow from PA.
That increased amount of blood flows from the RA to the RV and into the PA’s and less blood flows through the foramen ovale to the left atrium.
PFO closure from right side
The initial inflation of the lungs causes changes:
Decreases PVR results in increased blood flow from PA.
That increased amount of blood flows from the RA to the RV and into the PA’s and less blood flows through the foramen ovale to the left atrium.
PFO closure due to left side
In addition, more blood returns from the lungs which increases the pressure in the LA.
The increased LA pressure and decreased right atrial pressure (due to pulmonary resistance) forces blood against the septum primum causing the foramen ovale to close.
This action functionally completes the separation of the heart into two pumps
ostium primum location
located low in the septum and can be considered a type of AV septal defect.
ostium primum sat.
could have normal sat. in upper atrium but higher in lower atrium
sinus venosus location and associated with
located high in the septum where the vena cava intersects with the right atrium, frequently associated with partial anomalous venous return (PAPVR)
May be inferior and/or superior
Cardiac Septation - review
Occurs at ______ and lasts
day 27 and lasts 10 days
At day ____ the paired atria fuse together to form a
common atrium.
27-28
clinically remarkable left-to-right shunt
ASD > 9MM
Any process that increases the pressure in the LV can
cause worsening of the left-to-right shunt. It also works on the right heart
IF ASD LEFT uncorrected
ressure in the right heart > left heart.
RA pressure > LA pressure
The pressure gradient reverses across the ASD the shunt will reverse
a right-to-left shunt (R->L) will now exist.
This shunt reversal phenomena is known as
Eisenmenger’s syndrome
Once right-to-left shunting occurs
oxygen-poor blood gets shunted to the left side of the heart.
This will cause signs of cyanosis.
percutaneous closure of ASD aka
(Amplatzer)
types of surgical closure
Primary Closure Patch Closure
Surgical Correction of ASD’s
Incision:
Mediansternotomy
Right thoracotomy (going between the ribs on the right side)
Sub-mammary (under the breast tissue on the right front of the chest)-very difficult
Surgical Correction of ASD’s
Surgical Closure
Primary
– Closure by direct vision suture
Surgical Correction of ASD’s
Surgical Closure patch
– Uses pericardial tissue or Gore-Tex patch for closure
Surgical Correction of ASD’s
Surgical Closure patch
– Uses pericardial tissue or Gore-Tex patch for closure
ASD cannulation and VENTING
Arterial: Aortic
Venous: Bicaval (total CPB) Single Atrial if the infant is small and DHCA is
anticipated
Venting: may use direct venting with a flexible since the heart is open
ASD cardioplegia
Antegrade, usually a single dose will suffice
ASD case notes
Case is very, very quick, 5-10 min pump run Will XC, Stay warm “drift down temp”
Can be challenging: (on CPB, XC, give CP, warm, correct Ca++,lytes, ABG’s, off CPB-MUF)
A ventricular septal defect (VSD) is a
defect in the ventricular septum, the wall dividing the left and right ventricles of the heart.
The ventricular septum consists of:
Inferior muscular portion Superior membranous portion
Common Regions of Ventricular Septal Defects
Inlet Outlet (supracristal) Peri-membranous Septum Muscular Septum
prevalence of VSD
Membranous 75% Muscular 20% Supracristal (Outflow) 5%
Muscular ventricular septal defect is found in four locations
anterior, mid-ventricular, posterior, apical. Muscular VSDs are found in the lower part of the septum. They’re surrounded by muscle.
(most close on their own during early childhood.)
the membranous portion, which is close to the atrioventricular node, is most common in
adults and older children
Membranous VSDs are located near
the heart valves
membranous VSD can close
at any time.
Supracristal is an
outflow tract VSD sub-valvular in nature
The crista supraventricularis can be considered
synonymous with the infundibular (or conus) ventricular septum
Outlet VSDs are found in
the part of the ventricle where blood leaves the heart. These are the rarest type of VSD.
The infundibular (or conus) septum separates
the tricuspid and pulmonary valves and accounts for the more superior placement of the pulmonary valve relative to the aortic valve.
The infundibular (or conus) septum also provides
muscular rigid support for the aortic valve, especially the right coronary cusp (think prolapse)
The infundibular (or conus) septum also provides
muscular rigid support for the aortic valve, especially the right coronary cusp (think prolapse)
During systole, some of the blood from the left ventricle leaks
Into the right ventricle, passes through the lungs and reenters the left ventricle via the pulmonary veins and left atrium.
two net effects from VSD
First, the circuitous refluxing of blood causes volume
overload on the LV.
Second, because the left ventricle normally has a much higher systolic pressure (~120 mm Hg) than the right ventricle (~20 mm Hg), a LR shunt persists
this leakage of blood into the right ventricle elevates right ventricular pressure and volume, causing pulmonary hypertension
VSD pathophysiology is more noticeable
in patients with larger defects, who may present with breathlessness, poor feeding and failure to thrive in infancy.
Patients with smaller defects may be asymptomatic.
The ventricular septum is formed by the outgrowth
of the muscular ridge at the interventricular foramen.
vsd cannulation and venting
Arterial: Aortic Venous: Bicaval (Total CPB) Single Atrial if the infant is small and DHCA is anticipated
Venting: may use direct venting with a flexible since the heart is open
vsd cannulation and venting
Arterial: Aortic Venous: Bicaval (Total CPB) Single Atrial if the infant is small and DHCA is anticipated
Venting: may use direct venting with a flexible since the heart is open
vsd cardioplegia
Antegrade, usually a single dose will suffice
vsd case notes
Case is quick depending on VSD location
Case may be 32°C, or DHCA if a small infant
Can be challenging, but usually you have more time with VSD
ventricular function after case
may be related to of the length of time the VSD has been present
vsd percutaneous closure
Percutaneous closure (Amplatzer) Can be tough to close VSD’s percutaneously
surgical correction of VSD
Probably will not
see primary closure. mostly patch
