Left to Right Shunts Flashcards
Pulmonary vascular resistance (PVR) ___ from birth to 4-6 weeks of life– WHY?
Pulmonary vascular resistance (PVR) falls from birth to 4-6 weeks of life:
Infant begins to breathe
Arterial oxygen tension rises
Pulmonary arterioles dilate
Most L-R shunts do not result in symptoms during the first few weeks of life
Which defect?
Atrial Septal Defect (ASD)
Atrial Septal Defect (ASD) hemodynamics involves ___ to ____ communcation through the atria.
- volume overload of the ___ and the ___ leads to dilation.
an ASD increases ___ blood flow/vascularity
Atrial Septal Defect (ASD) hemodynamics involves LEFT to RIGHT communcation through the atria.
- volume overload of the RA and the RV leads to dilation.
an ASD increases PULMONARY blood flow/vascularity
T/F ASD symptomatology: Most are asymptomatic
True. most are asymptomatic
Shortness of breath with exercise later in childhood
and beyond
increased frequency of respiratory tract infections
rarely failure to thrive
+/- Arrhythmias later in life
ASD Cardiac Exam findings
___ heaves
fixed split ___
___ ejection murmur, loudest at ____ regioin.
Maybe a ___ murmur if the shunt is large.
RV heaves
fixed split S2
SYSTOLIC ejection murmur, loudest at LUSB regioin.
Maybe a DIASTOLIC murmur if the shunt is large.
ASD Management
if ASD is small, no treatment may be required
Although patients typically asymptomatic, closure of significant ASD is required to avoid complications of pulmonary hypertension, atrial arrhythmias
Large defects require either Surgical closure or Device closure
Type of defect
Ventricular Septal Defect
VSD Hemodynamics:
___ to __- shunt between ventricles.
the ___ pressure is hgiher than the ___ after birth. It is usually ___ at birth.
there is then increased ___ blood flow over time. There is therefore increased return of blood to the LA and LV, therefore ___ sided dilation occurs.
LEFT to RIGHT- shunt between ventricles.
the LV pressure is hgiher than the RV after birth. It is usually ASYMPTOMATIC at birth.
there is then increased PULMONARY blood flow over time. There is therefore increased return of blood to the LA and LV, therefore LEFT sided dilation occurs and therefore left strain.
Large VSD symptomatology– Why does congestive heart failure occur?
CHF in VSD occurs because of increased pulmonary blood flow.
- causes tachypnea, increased work of breathing.
- tachypnea, increased work ofbreathing
- difficulty feeding– diaphoresis, dyspnea, frequent breaks, longer tie to feed, reduced volumes
- tachycardia
- might be due to reduced perfusion.
- failure to thrive
VSD Cardiac Exam
- Active precordium ( because of tachypnea)
- thrills
- ___ S1 and S2
- ___ apex laterally and ingeriorly due to ___ dilation and volume overload.
- harsh ____ murmur loudest at the ___ radiating to ___.
- maybe a ___ rumble over the ___ area if the shunt is large.
- Active precordium ( because of tachypnea)
- thrills
- NORMAL S1 and S2
- DISPLACED apex laterally and inFeriorly due to LV dilation and volume overload.
- harsh PANSYSTOLIC murmur loudest at the LLSB radiating to APEX.
- maybe a DIASTOLIC rumble over the MV area if the shunt is large.
VSD CHF features on examination due to increased pulmonary blood flow:
- increased respiratory rate/tachypnea
- indrawing, nasal flaring, grunting, WOB
- crackles
- overall pulmonary hypertension symptoms. Recall that pulmonary hypertension is because of left sided heart failure from the VSD which is causing more left sided strain. the left side of the heart cannot pump blood out to the body normally, blood backs up in the lungs and increases blood pressure there. Inability of the heart to relax appropriately can also cause blood to back up into the lungs, which contributes to pulmonary hypertension.
Signs of systemic congestion:
right sided heart failure causes systemic congestion. Right sided heart failure often is caused by right sided heart fialure which first occurs in VSD
- hepatomegaly
- JVP not so easy to see in babies
- edema of eyelids (periorbital, labia/scrotum, sacral, hands and feet)
- pallor, cool extremities
VSD management
- spontaneous closure (75-80%)
- moderate to large defects
- surgical closure
- intiiatl therapy with diuretics and nutrition
- aim for 4-6 months for repair.
two non-surgical therapies for moderate to large surgical defects
initial therapy with diuretics and nutrition
type of defect
Atrioventricular Septal Defect
AVSD Hemodynamics:
___ shunt, complete mixing through the
hole that comprises both the atria and
ventricle (large defects)
Asymptomatic at birth before ___ falls
O2 saturations may be >85% with large AVSD
- Increased ___ blood flow as PVR
falls (can be earlier with large defects)
Similar signs/symptoms of ___ as a large
VSD
L-R shunt, complete mixing through the
hole that comprises both the atria and
ventricle (large defects)
Asymptomatic at birth before PVR falls
O2 saturations may be >85% with large AVSD
Increased pulmonary blood flow as PVR
falls (can be earlier with large defects)
Similar signs/symptoms of CHF as a large
VSD
Large AVSD - symptoms of CHF present early, usually sympatomatic 3-4 weeks of age.
ASVD CArdiac exam
- Cardiac apex displaced ___, LV lift, RV ___
- active precordium
- possible displaced apical impulse laterally/inferiorly
- ___ S1, ___ S2
- ___ ejection murmur at the ____ region
- possible ___ murmur of small-moderate VSD or ___ ___ at LLSB/Apex
- possible ___ rumble at LSB if large.
- Cardiac apex displaced LEFTWARD, LV lift, RV HEAVE
- active precordium
- possible displaced apical impulse laterally/inferiorly
- NORMAL S1, WIDE S2
- SYSTOLIC ejection murmur at the LUSB region
- possible PANSYSTOLIC murmur if small-moderate VSD or MITRAL REGURGITATION at LLSB/Apex
- possible DIASTOLIC rumble at LSB if large.
Type of defect
Patent Ductus Arteriosus
PDA Hemodynamics
- L- R shunt from __ to ___ artery
- Increased _ blood flow
- Increased return of blood to the _/_,
therefore __ sided dilation
- L- R shunt from aorta to pulmonary artery
- Increased pulmonary blood flow
- Increased return of blood to the LA/LV,
therefore left sided dilation (LA/LV dilation)
PDA findings on cardiac exam
+/- active precordium
+/- apex displaced laterally
__ S1 and S2
___ murmur 2nd left intercostal
space/___ (machinery quality)
___ pulses
PDA findings on cardiac exam
+/- active precordium
+/- apex displaced laterally
NORMAL S1 and S2
CONTINUOUS murmur 2nd left intercostal
space/SUBCLAVICULAR (machinery quality)
BOUNDING pulses
PDA management
SURGICAL LIGATION
- If PDA is small and not hemodaymically significant, no treatment required
Eisenmenger syndrome
- occurs over severeal years or decades
- results from undiagonsed ____ shunts later in life, more commonly due to large ___ and ___ shunts.
- due to increased __ blood flow over long periods of time start to change the pulmonary vascular bed. the pulmonary arteirs start to remodel and muscularize, results in increased __ ___ resistnace and ___ ___ pressure.
- evntually the pulmonary artery pressure exceeds systemic artery pressure–> results in pulmonary ___.
- the FLOW THROUHG THE SHUNT THEN REVERSES! Not shunting Right to left
results from undiagonsed L to R shunts later in life, more commonly due to large vsd and pda shunts.
- due to increased pulmonary blood flow over long periods of time start to change the pulmonary vascular bed. the pulmonary arteirs start to remodel and muscularize, results in increased pulmonary vascular resistnace and PA pressure.
- evntually the pulmonary artery pressure exceeds systemic artery pressure–> results in pulmonary hypertension.
- the FLOW THROUHG THE SHUNT THEN REVERSES! Not shunting Right to left
eisenmenger syndrome symptoms and potential complications
Eisenmenger Syndrome Cardiac Exam findings
- loud palpable ___
- RV___
palpable S2- recall that S2 is caused by closure of the pulmonic and aortic valves. Having increased pulmonary pressure and increased volume because of shunting causes the pulmonic valve to snap back at the pulmonic valve and close it quickly and hard.
- RV heave
