Download Congentital Heart Defects Sp 2015

Congenital Heart Defects (by Kimberly Napper)
Congenital Heart Disease
Occurs when the heart or blood vessels near the heart do not develop properly before birth.
May include structural defects, congenital arrhythmias, and cardiomyopathies
Are present in about 1% of live births
Are the most common congenital malformations in newborns
Definitions of terms:
Atresia- congenital absence or closure of a normal body opening or tubular structure
Prostaglandins- hormones important in the mediation of inflammation, platelet aggregation, vasodilation, pain
reception, & maintenance of patent ductus arteriosus
Prostaglandin inhibitors- nonsteroidal & steroid anti-inflammatory agents
Stenosis- constriction or narrowing of a passage or orifice
Subacute Bacterial Endocarditis (SBE)- heart valve infection not evident for weeks or months; usually
streptococcal; often develops on abnormal heart valve
SBE prophylaxis- to prevent SBE (antibiotics before “dirty procedures”
With Normal Heart Anatomy,
Oxygen-depleted blood is pumped from the right side of the heart, through the pulmonary artery, to the
lungs where it is oxygenated.
The oxygen-rich blood then returns to the left heart, via the pulmonary veins, and is pumped through the
aorta to the rest of the body.
Fetal Circulation (see Wong p. 823)
Umbilical vein supplies oxygen & nutrients from the placenta
Right side of heart has higher pressures than left side
Foramen ovale allows blood to cross from right to left atrium
Ductus arteriosus allows most of blood from pulmonary artery to enter the aorta
Transition from Fetal Circulation
Clamping of umbilical cord increases systemic pressure
Expansion of lungs with air
Increased oxygen decreases pulmonary pressure (vasodilation)
Promotes closure of ductus arteriosus
Closure of foramen ovale as left atrial pressure > right atrial pressure
Types of Congenital Heart Defects (Classifications) Wong p. 824
Acyanotic- left to right shunting of blood (↑pulmonary blood flow)
Cyanotic- right to left shunting of blood (↓pulmonary blood flow)
Acyanotic Defects (based on blood flow patterns within heart)
↑pulmonary flow (left to right shunting)
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ventricular septal defect
atrial septal defect
patent ductus arteriosus
Obstruction to blood flow out of the heart (not about shunting.)
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pulmonary stenosis (If severe stenosis, will be cyanotic)
aortic stenosis
coarctation of the aorta
Cyanotic Defects (based on blood flow patterns within heart) (See Wong 9th ed. p. 830-831.)
↓pulmonary flow
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Tetralogy of Fallot
Tricuspid Atresia
Mixed blood flow
Transposition of the Great Arteries
Truncus Arteriosus
Mixed blood flow
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Transportation of the great vessels
Truncus arteriosus
Acyanotic Defects ↑pulmonary flow (left to right shunting) (Left to Right Shunt (Wong p. 825))
Atrial Septal Defect (ASD) (See Wong 9th ed. p. 821, 826.)
Abnormal opening between the atria allows blood from higher-pressure left atrium to flow into lowerpressure right atrium (left to right shunt)
↑pulmonary blood flow with right heart dilation and pulmonary overcirculation
May have no symptoms until later in life
May have a soft systolic murmur
Repair can prevent serious problems later in life. (May lead to…)
Heart Failure (HF)
Atrial dysrhythmias
Pulmonary vascular obstructive disease
Emboli formation
Bubble Study to Confirm ASD http://www.youtube.com/watch?v=3dssbDeow50
Acyanotic Defects ↑pulmonary flow (left to right shunting) (Left to Right Shunt
Ventricular Septal Defect (VSD) (see Wong 9th ed. p.825, 826, 834)
Abnormal opening between the ventricles
Size & location of defect may vary
Allows blood from higher-pressure left ventricle to flow into lower-pressure right ventricle
↑pulmonary blood flow
HF is common due to flooding of the lungs & right ventricle ↑ load
Heart may enlarge from the added work
Murmur (sound of turbulent blood flow)
Respiratory distress “Head bobbing” & retractions are symptoms of this
http://www.youtube.com/watch?v=q0bHwMayCJY
http://www.youtube.com/watch?v=NBA9iigiDgk
If respiratory distress is R/T CHF, what medication should you give?
Increased pulmonary blood flow will cause prominent pulmonary vasculature (seen on CXR).
High blood pressure may occur in the lungs' blood vessels (because more blood is there)
Over time, increased pulmonary hypertension may permanently damage the blood vessel walls
May exhibit increased pulmonary vasculature on CXR.
VSD can be seen on Echocardiogram& is used to diagnose
Repair of VSD:
Small defects may close without surgery.
Small defects may be repaired surgically with a purse-string approach.
Large defects may be repaired using a Dacron patch.
Cardiopulmonary bypass is required for surgical repair.
Requires SBE prophylaxis until repaired.
Acyanotic Defects ↑pulmonary flow (left to right shunting) (Left to Right Shunt
Patent Ductus Arteriosus Wong 9th ed. p. 827
The 6th most common congenital heart defect (5 to 10% of all children with CHD)
Occurs twice as often in girls as in boys
Depending on the size of the PDA and the condition of the lungs, there may be no symptoms or
severe heart failure.
In utero, the ductus is a normal connection between the aorta and the pulmonary artery
At birth, hormonal changes normally cause its closure
Failure to close may cause excessive blood flow to the lungs & the pulmonary arteries will
dilate due to the increased pulmonary blood flow
http://en.wikipedia.org/wiki/Image:Patent_ductus_arteriosus.jpg
S/S, if hemodynamically significant:
CHF/respiratory distress, congestion in the lungs, prominent pulmonary vascular
markings seen on CXR
Machinery-like murmur
Widened pulse pressure, Bounding pulses, Pedal & periorbital edema
Repair of PDA:
May be “ligated” in surgery
May be closed in cath lab by inserting specially designed coils, which block blood flow
in the vessel
May be closed medically with Indomethacin (blocks Prostaglandins)
Ibuprofen as an alternative (piloted in 2003)
Inhibition of prostaglandin synthesis permits constriction of the PDA
FDA-approved Indomethacin for use when S/S persist after 48 hours of
conservative treatment (fluid restriction, diuretics, and respiratory support).
Side effects of prostaglandin-inhibiting medicines (Indomethacin & Ibuprofen):
Gastrointestinal problems: abdominal distention, bleeding, gastric perforation
Transient ileus, vomiting
Renal function impairment
Bleeding problems
Hypoglycemia
Patent Ductus Arteriosus (PDA) (cont.)
Shunting of blood can also be right to left, depending on the difference in pressures between
systemic & pulmonary circulation (Blood flow will follow the path of least resistance.)
PDA may be life-saving in some cases (see Wong 9th ed. p.832)
Prostaglandin (PGE1) will be given IV to keep ductus from closing in these cases
Studies performed prior to the initiation of prostaglandin therapy for central cyanosis:
Hyperoxic Challenge Test
Chest x-ray: Decreased pulmonary vascularity
Serum glucose
Hematocrit
Adequate ventilation
Arterial Blood Gases
Definitive echocardiography and cardiac catheterization will clearly identify
infants with “ductal dependent” pulmonary blood flow
Prostaglandin E1 is infused continuously by pump via a large peripheral vein or umbilical line.
During treatment with PGE1, monitor respiratory rate, temperature, blood pressure, arterial
blood gases and pH.
Three common side effects of PGE1: apnea (12%), fever (14%), flushing (10%)
Obstruction to Blood Flow out of Heart (Acyanotic Defects)
An obstruction is a narrowing that partly or completely blocks the flow of blood.
Obstructions called stenoses can occur in heart valves, arteries or veins.
The three most common forms are pulmonary stenosis, aortic stenosis and coarctation of the aorta.
Pulmonary Stenosis (PS) (Classified as Obstruction to Blood Flow out of Heart)
The pulmonary or pulmonic valve is between the right ventricle and the pulmonary artery.
It opens to allow blood to flow from the right ventricle to the lungs.
A defective pulmonary valve that doesn't open properly is called stenotic.
This forces the right ventricle to pump harder than normal to overcome the obstruction.
If severe, may be a cyanotic defect.
Treatment is needed when the pressure in the right ventricle is higher than normal.
In most children, the obstruction can be relieved by a procedure called balloon valvuloplasty.
Others may need open-heart surgery.
Requires SBE prophylaxis
Critical Pulmonary Stenosis/ Pulmonary atresia (Classified as Obstruction to Blood Flow out of
Heart)
No blood flow to lungs through pulmonic valve (total fusion of commissures)
Decreased pulmonary vasculature (seen on CXR)
Hypoplastic right ventricle may accompany
Cyanosis if PDA closes PDA needed for survival until surgical repair.
Prostaglandins to keep ductus open
Aortic Stenosis (AS) (Classified as Obstruction to Blood Flow out of Heart, Acyanotic Defect)
A normal valve has three leaflets (cusps).
A stenotic valve may have only one cusp (unicuspid) or two cusps (bicuspid), which are thick
and stiff.
The left ventricle will have difficulty in pumping blood to the body through this abnormal valve.
Symptoms may be severe in some infants
Most children have no symptoms
Some children may have chest pain, unusual tiring, dizziness or fainting
The need for surgery depends on how bad the stenosis is
Valve opening may be enlarged by balloon valvuloplasty or surgery.
The valve will remain deformed.
The valve may need to be replaced with an artificial one.
Lifelong medical follow-up is required
AS may worsen over time, and surgical relief of a blockage is sometimes incomplete
Some exercise may be restricted (like heavy lifting)
SBE prophylaxis is required
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The Aorta is the body's main artery.
It distributes oxygen-rich blood to all parts of the body except the lungs
The first branches of the aorta go to the upper body (arms and head)
After that, blood goes to the lower body (abdomen and legs)
Coarctation of the Aorta (Classified as Obstruction to Blood Flow out of Heart, Acyanotic Defect)
(See Wong 9th ed. p. 827, 828.)
http://www.heart.org/HEARTORG/Conditions/CongenitalHeartDefects/AboutCongenitalHeartDefects/
Coarctation-of-the-Aorta-CoA_UCM_307022_Article.jsp
Is a narrowing of the aorta between the upper-body artery branches and the branches to the lower
body
May include aortic valve abnormalities
May be associated with other cardiac defects
SBE prophylaxis indicated
Increases blood pressure in the arms and head
Average B/P in a newborn is 64/41.
Average B/P in a child 1 month - 2 years is 95/58.
Reduces blood pressure in the legs
Diminished pulses in lower extremities
Seriously strains the heart
Leads to cardiomegaly
Leads to CHF (heart failure)
Severe Coarctation of Aorta
In severe cases, cyanosis if PDA closes
Patient needs PDA for survival until surgical repair
Prostaglandins (PGE1) to keep ductus open
Repair of Coarctation of the Aorta
Balloon repair
Risk of restenosis or aneurysm
Surgical repair
Preferred in infants < 7 months
Cyanotic Defects (decreased pulmonary flow)
Tricuspid Atresia
Tetralogy of Fallot
Transposition of the Great Vessels
Truncus Arteriosus
Tricuspid Atresia (Cyanotic Defect (decreased pulmonary flow)) Wong 9th ed. p.831
No tricuspid valve so no blood can flow from the right atrium to the right ventricle
Right ventricle is small and not fully developed
Survival depends on presence of ASD/VSD
At birth, the PFO and PDA provide mixing
Prostaglandin E1 to prevent ductal closure prior to surgical repair
Tricuspid Atresia Blood Flow:
Right atrium → ASD → left atrium →
Most of this blood flows left ventricle → aorta → body
The rest flows through the VSD → small right ventricle →
pulmonary artery → lungs
Because of poor pulmonary circulation, the child looks blue.
Tricuspid Atresia repair: requires multiple procedures
Atrial septostomy in cath lab
Pulmonary to systemic artery anastomosis (Blalock and Taussig (BT) shunt)
Bidirectional Glenn shunt at 6-9 months (2nd stage)
Modified Fontan procedure
Nursing Considerations re: Tricuspid Atresia repair
No blood pressures or venipunctures in left arm of patients who had Glenn procedure (because
the left subclavian artery used as a shunt, so blood pressure will not reflect client’s true blood
pressure)
Family support & teaching regarding multiple surgeries & mortality rate ~10%
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Tetralogy of Fallot (Cyanotic Defects (decreased pulmonary flow)) Wong 9th ed. p.841
4 Key Features:
1. Ventricular Septal Defect (a hole between the ventricles)
2. Pulmonary Stenosis (obstruction from the right ventricle to the lungs)
3. Overriding Aorta (the major artery from the heart to the body lies directly over the
ventricular septal defect)
4. Right Ventricular Hypertrophy (thickened muscle develops)
Boot-shape on CXR
Often blue (cyanotic) since some oxygen-poor blood is pumped to the body
Blood from both ventricles (oxygen-rich and oxygen-poor) is pumped into the body since
the aorta overrides the ventricular defect and there's pulmonary stenosis
May have pulmonary atresia (pulmonary valve completely obstructed)
http://www.heart.org/HEARTORG/Conditions/CongenitalHeartDefects/AboutCongenitalHeartD
efects/Tetralogy-of-Fallot_UCM_307038_Article.jsp
Surgical Treatment of Tetralogy of Fallot
In small and very blue infants, a shunt operation may be done first to provide adequate
blood flow to the lungs.
The shunt is built between the aorta and the pulmonary artery
The shunt is removed when a complete intracardiac repair is done later
“Tet Spell” (hypercyanotic spell) See Box 25-3 p. 830 Wong, & Box on p. 842 Wong
Squatting Position
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Mixed blood flow
Transposition of the Great Vessels or Transposition of the Great Arteries (TGA)
Truncus Arteriosus
Transposition of the Great Vessels or Great Arteries (Mixed blood flow defect)
http://www.heart.org/HEARTORG/Conditions/CongenitalDefectsChildren&Adults/AboutCongenitalHe
artDefects/d-Transposition-of-the-great-arteries_UCM_307024_Article.jsp
“Egg on a String” on CXR
Aorta comes off RV (right ventricle)
Pulmonary Artery comes off LV
Cyanosis (Less severe if large ASD, VSD, or PDA)
CHF if ASD, VSD, or PDA
Patent Foramen Ovale (PFO) commonly present
PDA, PFO, & septal defects allow mixing of blood (to get flow to the lungs)
Prostaglandins to keep ductus open, if no other means of mixing left & right circulation
Treatment of Transposition of Great Vessels:
Balloon Atrial Septostomy to establish mixing
Surgical switch of vessels
Truncus Arteriosus (Mixed blood flow defect)
Boot shape on CXR
Single vessel that overrides both ventricles pulmonary artery & aorta share a trunk
Blood from left & right mix in single vessel
Hypoxemia
↑ Pulmonary flow (R/T pressures)
↓ Systemic blood flow (R/T pressures)
Surgical repair in first month of life:
Closure of VSD & Grafts to connect pulmonary arteries to right ventricle
Post repair complications
CHF common
Pulmonary hypertension
Dysrhythmias
Mortality >10%
Future surgeries required to replace conduits
Developmental Care of the Sick Infant
Bonding: (See Wong 9th ed. p 843.)
Kangaroo Care:
Holding a diaper-clad infant in skin-to-skin contact, prone and upright on the chest of the parent.
Infant enclosed in parent’s clothing to maintain temperature stability.
Recommended for medically stable infants, infants receiving palliative care
Positioning Aids:
Maintain flexion of the limbs
“Tummy time”
Complications of Congenital Heart Defects
Bacterial Endocarditis
Pulmonary Hypertension
Congestive Heart Failure
Arrhythmias
Emboli
Bacterial Endocarditis. (Complications of Congenital Heart Defects)
When blood is pumped at high pressure through defects, the lining of the heart tissue will become
irritated and inflamed
Bacteria in the bloodstream can easily infect this injured area, causing a serious illness known as
bacterial endocarditis
“SBE Prophylaxis”
SBE=Subacute Bacterial Endocarditis
Prophylaxis = prevention
“SBE Prophylaxis” indicated for:
All cyanotic heart lesions, especially those with systemic-to-pulmonary shunts in place
All post-operative coarctation patients, whether surgically repaired or after balloon dilation
All those with valvar abnormalities, whether congenital, rheumatic, or with prosthetic valve in
place
VSD patients: the smaller the VSD, the higher the chance of SBE
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Cardiac Conditions Associated With Endocarditis: (all of these defects except ASD- know this.)
Just read this section for your information. Do NOT try to memorize for testing purposes! 
High-risk category:
Complex cyanotic congenital heart disease (single ventricle states, transposition of the great
arteries, Tetralogy of Fallot)
Prosthetic cardiac valves
Previous bacterial endocarditis
Surgically constructed systemic pulmonary shunts or conduits
Cardiac Conditions Associated with Endocarditis
Moderate-risk category:
Most other congenital cardiac malformations
Acquired valvar dysfunction (e.g., rheumatic heart disease)
Hypertrophic cardiomyopathy
Mitral valve prolapse with valvar regurgitation and/or thickened leaflets
Endocarditis Prophylaxis for
Dental extractions
Periodontal procedures
Root canals
Initial placement of orthodontic bands but not brackets
Prophylactic cleaning of teeth or implants (where bleeding is anticipated)
Standard Regimen
Amoxicillin PO 1h before procedure or
Ampicillin IM/IV 30m before procedure
If Allergic to Penicillin
Clindamycin, Cephalexin, Cefadroxil, Cefazolin, Azithromycin, or Clarithromycin
Vancomycin or Gentamycin for higher risk
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Pulmonary Hypertension (Complications of Congenital Heart Defects)
Large volumes of blood pumped to the lungs →
high pressure
Blood vessels in the lungs become damaged by the extra pressure
Pressure builds up in the lungs → ↓ blood flow from the left heart to the right heart (preserves lung
function)
Blood flow in the heart goes from areas of high pressure to areas of lower pressure
Pulmonary Hypertension and “Shunting” right to left
If defects causing high blood flow to lungs persist, lung disease will develop
Pressure in the right heart will become higher than in the left heart
Oxygen-poor blood will flow from the right side of the heart (via ASD/VSD/PDA) into the left
side (and out to the body)
When there is an opening or passage between the atria, ventricles, and/or great vessels
… and …
Right heart pressure is higher than left heart pressure, the blood will shunt away from the lungs (right to left)
Pulmonary hypertension can be a lifelong condition because of CHD. It may also develop later in life in a client
who has not had a heart defect because of other factors.
http://www.heart.org/HEARTORG/Conditions/HighBloodPressure/AboutHighBloodPressure/What-isPulmonary-Hypertension_UCM_301792_Article.jsp
Congestive Heart Failure (Complication of Congenital Heart Defects) (See Wong 9th ed. p 391.)
Right-sided failure if difficult to pump blood to pulmonary artery, ↑pressure develops in right atrium &
systemic venous circulation → hepatosplenomegaly & edema
Congestive Heart Failure is caused by conditions that require the heart muscle to work hard.
Failure of one side of heart leads to failure of the other side due to reciprocal changes.
Presenting symptoms may vary:
Impaired myocardial function, Pulmonary congestion, Systemic venous congestion, Tachypnea,
Tachycardia (at rest), Dyspnea, Retractions, Activity Intolerance (poor feeding) (See Wong 9th ed. p
840.), Enlarged liver, Enlarged heart on CXR (& on EKG), ↑pulmonary blood flow on CXR
http://www.heart.org/HEARTORG/Conditions/CongenitalHeartDefects/TheImpactofCongenitalHeartDefects/C
ongestive-Heart-Failure_UCM_307111_Article.jsp
Heart failure (HF) can occur in adults who do not have a congenital heart defect. Hypertension is a common
cause, but there are other causes of HF. The treatment is similar to that for an infant.
http://www.heart.org/HEARTORG/Conditions/HeartFailure/AboutHeartFailure/About-HeartFailure_UCM_002044_Article.jsp
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Congestive Heart Failure Treatment Goals (see Wong)
↓ afterload by vasodilation (ACE inhibitors)
↑ cardiac contractility (glycoside: Lanoxin)
↓ preload by removing excess fluid & sodium (diuretics: Lasix & thiazides)
↓ cardiac demands (rest & homeostasis)
Improve tissue oxygenation & ↓ oxygen consumption (O2 administration)
Oral medication administration. Know how to safety give to an infant & what to teach caregiver.
ACE inhibitors (↓ afterload by vasodilation)
Lower blood pressure by decreasing the formation of a potent vasoconstrictor (so, vasodilation occurs)
Common adverse drug reactions include: hypotension, cough, hyperkalemia, headache, dizziness,
fatigue, nausea, renal impairment
Captopril (Capoten®) often used in pediatric population
Cardiac glycosides (↑ cardiac contractility)
Inhibit the Na+/K+ pump →
↑ sodium ions in the myocytes →
↑ calcium ions →
↑ amount of Ca++ ions available for contraction of the heart muscle →
improves cardiac output and reduces distention of the heart
Digoxin (Lanoxin) commonly used (Cardiac glycoside) see also Wong 9th ed. p. 836
IV with “loading dose”
Serum levels for safety & efficacy (Usual range is 0.8 to 2.0 ng/mL)
PO for maintenance
Check apical pulse before administering: hold if HR < 90 – 110 infants, < 70 older children
S/S toxicity (more likely if serum potassium levels are abnormal)
*Nausea, Vomiting, Anorexia, Bradycardia, dysrhythmias
Diuretics: (↓ preload by removing excess fluid & sodium)
HCTZ (hydrochlorothiazide) & furosemide (Lasix) are commonly used in pediatric clients.
Routes: po, IV
Works by blocking the absorption of salt and fluid in the ascending loop of Henle, causing a
profound increase in urine output (diuresis)
Can cause lowering of blood potassium, sodium, and magnesium levels, which can lead to heart
rhythm abnormalities, especially in patients already taking digoxin
Diagnostic Tests
Chest X-ray- used to visualize size of heart & evaluate pulmonary edema & other lung problems
Electrocardiogram- to evaluate heart’s electrical conduction
Echocardiogram- view anatomy of heart & valves, measure ejection fraction, check movement of heart
Cardiac CatheterizationDiagnostic (evaluate structure & blood flow)
Interventional (to correct anatomical problems)
Echocardiogram (Echo) Ejection fraction (EF) & pulmonary artery pressures can be measured during this test.
A procedure that evaluates the structure and function of the heart by using sound waves recorded on an
electronic sensor
Produces a moving picture of the heart and heart valves
Can show the pattern of blood flow through the septal openings & determine how large the openings are
& how much blood is passing through them
Ejection fraction is measured to evaluate how much blood the left ventricle pumps out with each
contraction. Very useful for evaluating heart failure.
http://www.heart.org/HEARTORG/Conditions/HeartFailure/SymptomsDiagnosisofHeartFailure/Ejectio
n-Fraction-Heart-Failure-Measurement_UCM_306339_Article.jsp
BNP (brain natriuretic peptide) is a blood test that helps diagnose heart failure.
Elevated levels indicate HF. The level should decrease in response to treatment.
https://my.clevelandclinic.org/services/heart/diagnostics-testing/laboratory-tests/b-type-natriureticpeptide-bnp-bloodtest
Cardiac Catheterization (not generally used to diagnose heart failure)
An invasive procedure that uses contrast dye to visualize the structures inside the heart
Under sedation, a small, thin, flexible tube (catheter) is inserted into a blood vessel in the groin and
guided to the inside of the heart
Blood pressure & oxygen measurements are taken in the four chambers of the heart & in the pulmonary
artery and aorta
Usually not required for patients less than 6 months of age, but interventional cath may be done for very
sick infants. (For example, a balloon septostomy might be done to provide mixing of blood for an infant
with a heart defect that causes cyanosis.)
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