Download Obstructive Congenital Heart Disease

David Reilly
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Congenital Heart Disease I
A. INTRODUCTION
I. Definitions/Epidemiology
1.Congenital Heart Disease (CHD)
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Any structural cardiac malformation present at birth
 Leading cause of death due to congenital malformations
 Prevalence of 8/1000
2.Critical CHD
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CHD that presents in early infancy w/ life threatening congestive heart failure or ductal-dependence.
3.Most common CHDs:
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#1 Ventricular Septal Defect!!
Pulmonic stenosis, Atrial Septal defect (ASD), AV canal, Teratology of fallot (ToF), Dextro-position of the
great vessels (d-TGA), Patent ductus arteriosus (PDA), Aortic stenosis (AS), Hypoplastic left heart syndrome
(HLHS).
II. Transitional Physiology
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The most important two changes during birth w/ respect to the heart:
 1. Reduction of pulmonary vascular resistance and increase of systemic vascular resistance (begins
to transition pressure loads from RL heart.
 2. Closure of the Ductus Arteriosus (as well as ductus spinosus, and foramen ovale.
B. ACYANOTIC CONGENITAL HEART DISEASE (LR SHUNTS)
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Blood passes from Left to Right heart (high pressure/oxygenated “red” systemlow pressure/deoxygenated
“blue” system)
Results in “over circulation” of the pulmonary system (greater flow through lungs than body, when it should be
equal)
 Qp:Qs ratio is > 1
I. Atrial Septal Defect (ASD) 5-10%
1.Physiology
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Opening between L and R atrium.
 Ostium secundum>Ostium primum
Flow from LR atrium (all the time since L pressure is always higher than Right)
Increased volume load on Right heartenlargement (hypertrophy and dilation) of RA, RV and
pulmonary artery.
2.Physical Exam
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Depending on size, often asymptomatic.
 Classic findings:
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1) Systolic Ejection murmur across pulmonic valve (functionally stenotic due to increased flow)
2) Fixed splitting of S2- P takes longer to close due to volume
3) Mid-diastolic S3 rumble- large flow across tricuspid valve
# note: there is no direct ASD murmur- pressures are too low to generate sound-murmurs all stem from
volume.
3.Tests
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ECG: Right ventricular hypertrophy, findings of a RBBB (rSR’)
4.Treatment
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Small shunts may close on their own
Surgical or catheter approaches to close the hole.
II. Ventricular Septal Defect (VSD) ***20%!! (most common)
1.Physiology
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Communication between L and R ventricles (many types depending on location on Interventricular septum)
**magnitude of shunt determined by size of defect AND pulmonary vascular resistance (PVR)
 More resistance = less shunt, Less resistance = More shunt
Note: both ventricles contract at the same time- thus they essentially act as one pushing blood into
the pulmonary artery. As a result the first structures to feel the volume overload is the Pulmonary
artery, Left atrium and left ventricle!!!!!! they enlarge first!
David Reilly
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Remember: It is a competition between Aortic and Pulmonic outlet. As long as systemic resistance
is low the LV will eject that way… but, by 4-6 weeks Pulmonary resistance is at its lowest and
systemic is at its highest.
Ultimately the RV will enlarge as pulmonary HTN develops and it must work against the resistance
2.Physical Exam
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Murmur: Holosystolic at the left sternal border
Large shunts will also have a left sided S3 due to large volume across the mitral valve
With Severe VSD- the pulmonary HTN that develops secondary to LA/LV hypertrophy causes symptoms of
Heart failure and a loud P2.
3. Natural History and management
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Small VSDs may close
Symptomatic VSDs (CHF) treated with heart failure meds until surgery
Eisenmenger physiology- Late Complication w/o surgery
 Pulmonary HTN becomes so severe that the ventricular shunt reverses (RL) and cyanosis can
ensue.
III. Patent Ductus Arteriosus (PDA)
1.Physiology
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LR shunt between the Aorta and Pulmonary artery
Because aortic pressure is ALWAYS higher than pulmonary the flow is CONTINUOUS and only limited by
resistance to flow across the PDA.
First chambers to enlarge: LA, LV, and Pulmonary artery
2.Physical Exam
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PDA murmur: Continuous
“Bounding” pulse: Wide pulse pressure d/t large ejection, with run off into lungs during diastole
3.Treatment
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Indomethacin- in premature infants to naturally close
Surgery- easy surgery, non-invasive methods are available.
IV. Complete Common Atrioventricular Canal (CCAVC) aka “AV canal”
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ASSOCIATED W/ TRISOMY 21 (Downs=30% of CHD, 15% of which is AV canal)
1.Physiology
3 “strange” findings:
 1. LV-RV fistula (Inlet type VSD)
 2. LA-RA fistula (Primum Septum type ASD)
 3. A “common” 5-leaflet super valve between the atria and ventricles (usually regurgitant)
# basically the center of the heart is replaced with a giant valve
# results in mixing of blood which can cause desaturation and cyanosis if severe!!
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2.Tests
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ECG: Left Axis devation
Echo: assess the finer points of the anamoly
3.Management
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Close the ASD and VSD
Create two separate valves from the super-valve
 NOTE: The new mitral valve is often regurgitant… best we can do
C. OBSTRUCTIVE CONGENITAL HEART DISEASE
I. General changes
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Compensatory hypertrophy in the upstream chamber
Thick, deformed immobile leaflets
“Ejection click” w/ opening of stenotic valve
Crescendo-Decrescendo Ejection Murmur- associated w/ diastolic regurge if severe.
Post-stenotic dilation
II. Pulmonic Stenosis 5-8%
1. Types
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Can be Subvalvar, Infundibular (in teratology of fallot), valvar (most common) and supravalvar
Critical PS= ductal dependence for pulmonary perfusion.
2.Physical Exam
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Murmur: Louder and peak later w/ increased severity
Signs of Right heart failure if severe (see stenosis lecture)
3.Tests
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David Reilly
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ECG: RV hypertrophy
Chest X-Ray: Cardiomegaly. Post-stenotic Dilation
4.Management
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Valvular- Balloon Valvuloplasty
Dysplastic valves and subvalvular- require surgical intervention
III. Aortic Stenosis 5%
1.General
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Male>female
Obstruction can be Supra- (coarctation), Sub- (HOCM) and valvar.
**Bicuspid Aortic Valve is the most common congenital abnormality and MAY result in AS
Critical AS= Ductal dependence for systemic circulation
2.Physical Exam
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Murmur: Holosystolic Crescendo-Decrescendo heart best at Aortic site with radiation to carotids.
 Severity correlates w/ Later and louder peaking of murmur AND presence or absence of companion
diastolic aortic regurg.
3.Management
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See lecture on AS
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