Download The Beat Goes On: A Review of Congenital Heart Defects

The Beat Goes on…
A Review of Congenital Heart Defects(CHD)
Thomas P Carey J, MPH RRT Professor of Allied Health and RC
Program Director
Pretest….
• What the heck I’m on break-you are never on break
• Name 3 maternal medical conditions that might put the newborn @ risk for
CHD?
• Name the 2 mechanisms that shunt blood away from the heart.
• Define a heart murmur.
• Name a acyanotic CHD with increased pulmonary blood flow.
• Name a cyanotc CHD with a decreased pulmonary blood flow.
• Name a acyanotic CHD that obstructs blood flow.
• ASD, VSD, PDA, Coarctation of the Aorta(COA), Aortic Stenosis, Pulmonary
Stenosis, TOF, Tricuspid Atresia, Truncus Arteriosus, Hypoplastic Lf heart
Syndrome, TGA
Statistics
• Over 1.3 million Americans alive today have some form of congenital
heart defect.
• In the US, about 40,000 children are born with a heart defect each year
with a higher incidence in premature infants.
• At least eight of every 1,000 infants born each year have a heart defect.
• The causes of congenital heart disease are still under investigation.
• Usually caused by developmental abnormalities during gestational
weeks three through eight.
Fetal heart 20 weeks
•The cardiovascular
system is the first
organ system to
develop and function
in the fetus.
Causes of Heart Defects
• Unknown cause: Likely due to a combination of multiple
genetic and environmental factors. There's usually a 2 to15
percent chance of a heart defect happening again in the
family.
• Genetic syndrome: Pts that have a specific genetic condition
that can include other health problems. (Down Syndrome)
• Single gene: Rarely, congenital heart defects are caused
by changes in a single gene.
• The chance for another family member to have a heart
defect can be as high as 50 percent.
• A missing piece (deletion) of genetic material on
chromosome 22 also causes heart defects.
• Incest is also a cause.
Medical conditions in mom
• Diabetes
• Systemic Lupus Erythrematosus
• Rubella (German measles) in the first 3 months of
pregnancy
• Obesity A BMI over 30.
• Phenylketonuria (PKU)
lifestyle and environment
• These include:
• Smoking before or during pregnancy(go figure)
• Drinking alcohol during pregnancy
• Medications known to increase the risk of congenital heart
defects include thalidomide (Thalomid), the acne medication
(Amnesteem, Claravis, Sotret), lithium and anti-seizure
medications containing valproate.
Quick review of fetal circulation
•Think back…
•Remember when
you were a fetus?
•Life was good!
Cardiopulmonary Changes at Birth
• Body Structure
• Ductus Arteriosus
• Foramen Ovale
Before Birth
After Birth
Shunts blood from PAAorta Closes functionally within
min-hrs(days in premies) due to
O2, metabolism of PGE2 by
lungs and release of bradykinin
and histamine. Permanent
closure by 2-4 mos. ligamentum
arteriosum formed within 3
weeks of birth.
Shunts blood from RA to LA
Functionally closes within minshrs. due to increase P
(LAP>RAP) caused by
increased Pulm Blood flow and
increased SVR. (seals in 3 mo)
• Body Structure
• Pulmonary Arteries
100% of
decrease PVR <25,
to increased PO2,
expansion, release
bradykinin
Before Birth
After Birth
Carry only 10% of blood flow Dilates to carry
Increased PVR(vasoconstriction)
C.O.,
60 mmHg
due
lung
of
• Systemic Circulation
LV
Low P in LA, LV and aorta
Increase SVR, Increase
work
Clinical Manifestations(general)
•Heart Murmur
•Hypoxemia
•Poor feeding
•Poor Wt gain
•Tachypnea
•S&S of CHF
murmurs
• Murmurs are heart sounds that are related to turbulent flow
through an abnormal opening or through a restricted or
obstructed area
• Intensity is based on a grading scale:
• Grade I = barely audible
• Grade II = Clearly audible
• Grade III = Moderately Audible
• Grade IV = Loud, associated with a thrill
• Grade V = Very Loud
• Grade VI = Loudest-heart with scope off of chest
• PDA heart sound
• VSD Heart murmur
S/S of Cardiac Disease in infants
• 1. Cry: weak and muffled, loud and breathless
• 2. Color
• A. Cyanotic: usually generalized; increases in supine position;
often unrelieved by oxygen, usually deepens with crying;
gray, dusky cyanosis –mild, moderate, severe.
• B. Acyanotic: pale, with or without mottling on
excertion
•3. Activity Level
•a. Restlessness
•b. Lethargic
•c. Unresponsive except to pain
•d. Lack of movement of arms and legs when crying
•e. Arms become flaccid when eating
• 4. Posturing
• a. Hypotonic: flaccid even when sleeping
• b. Hyperextension of neck
• c. Opisthotonos-(A great rigid spasm of the body, with the back
fully arched and the heels and head bent back.)
• d. Dyspnea when supine
• e. Favors knee-chest position- this increases systemic vascular
resistance, and will also decrease the right to left shunting of
deoxygenated blood into the systemic circulation
•5. Persistent bradycardia – 120 bpm – or
persistent tachycardia – 160 bpm
6. Respirations: counted when neonate is sleeping to
identify problem early
A. Tachypnea: 60 breaths/minute
B. Retractions with nasal flaring or
tachypnea
Congenital Heart Disease
•3 Major Categories:
1. Acyanotic Heart Disease(nonhypoxemic)
•Blood shunts left to right causing CHF
2. Cyanotic Heart Disease(hypoxemic)
• Blood shunts from right to left, bypassing lung.
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977,
1973, 1969 by Mosby, an imprint of Elsevier Inc.
22
•3. Obstructive Lesions ; produce blood flow
across the stenotic area with hypertensive
changes proximal to the obstruction which may
have hypo perfusion states distally.
Comparison of Acyanotic and cyanotic heart disease
• Feature
Acyanotic
• Shunting of blood
Cyanotic
Left to Right
Right to
Left
• Cyanosis
Not usual(unless CHF)
• Surgery
Technically Simple
•
• Prognosis
• Major Types
Always; blue babies
Technically complex
usually done in several stages
Very good/excellent
Guarded
ASD, VSD, PDA, COA
Tetralogy of Fallot(TOF)
•
Transposition of Great Vessels
• Cyanosis – evident with a arterial O2 sat < 85%
• Acrocyanosis is common in newborns and reflects unstable
peripheral vasomotor tone.
• Is the cyanosis due to lung disease or heart disease?
• Perform a hyperoxygenation test:
• place infant on 100%,
• if the sats improve with O2 then the cyanosis is most likely
due to lung disease
• With no change in cyanosis(or sats) on 100% O2, then
heart disease is expected
Diagnostic procedures for CHD
•Assessment of oxygenation and ventilatory
status (intubation and MV necessary in
severe CHD cases, especially CYANOTIC HD)
•
Auscultated heart murmur, Echocardiography,
cardiac cath, EKG, ultrasound and CXR
Acyanotic heart defects with increased
pulmonary blood flow
Atrial Septal Defects,
Ventricular Septal Defects,
Atrioventricular Septal Defects,
Patent Ductus Arteriosus
Atrial Septal Defect
• Abnormal opening in the
atrium septum
• Blood flows from LA to RA
• Usually asymptomatic
• ASD’s vary in size and in the
severity of symptoms they
may cause.
• Twice as prevalent among
girls as boys
ASD- pulmonary blood flow and RA
and RV volume are increased
• Usually asymptomatic
and undetected until
adulthood, when
increased left-to-right
blood flow can result in
RA and RV hypertrophy.
Clinical manifestations-ASD
• Heart murmur caused by the extra blood flow across the
pulmonary valve.
• Small ASD-no symptoms, less than 2mm-there is a high
probably it will close on its own
• Larger ASD- infants may develop CHF due to higher blood
flow into RA,RV and PA. This enlarges the RA and RV, distorts
shape of PA and (rarely)blood vessels in the lung
Diagnosis(Dx) and treatment(TX)
Dx- Auscultated heart murmur,
Echocardiography(primary method), EKG,
ultrasound and CXR-enlargement of the heart
and increased pulmonary blood flow.
Tx- Asd may close on its own. An ASD still
present at 3 yrs of age probably won’t close
on its own.
Open Heart Surgery-surgical closure
Amplatzer Septal Occluder
Ventricular Septal defect-VSD
• Most common CHD
• May occur as a isolated defect or
in association with other
defects(TOF)
• Left to Right shunt increasing
pulmonary blood flow
• Heart murmur due to turbulent
blood flow crossing the hole. The
smaller the hole the louder the
murmur.
• Can cause RV hypertrophy and
Pulmonary HTN.
Clinical manifestations
• Depends on the size, location and
number of holes.
• Small holes usually no s/s and close
naturally.
• Larger results in CHF with the following
symptoms:
• Sweating, Fatigue, Tachypnea, congested
breathing, disinterest in feeding and
poor wt gain.
Diagnosis
• Dx- Auscultated heart
murmur, Echocardiography,
EKG, ultrasound and CXRenlargement of the heart and
increased pulmonary blood
flow.
• (same as ASD)
Treatment
•Small VSD’s may close on their own.
•Larger VSD- catheter based closure, open
heart surgery patching or suturing.
•Treat infants in CHF - Lasix and digoxin as
surgery awaits
Patent Ductus Arteriosus(PDA)
• The fetal shunt between the
PA and the aorta does not
close.
• Blood is shunted from the
aorta to the PA Left to Rt
shunt
• Accounts for 5-10% of CHDs
• Male to female ratio 1:3
PDA
•Risk Factors:
Gestational age:
Premature Infants < 1000gm=approx. 80%,
1000-1750 gm = approx. 45%, Term 5-10%
Presence of respiratory disease during ventilation
Meconium aspiration
• Normally closes within up to
24hrs after birth, 90% by 48hrs,
100% by 96hrs
• Blood flows from aorta to PAincreasing blood flow to the
lungs but also increasing blood
flow to LA via PVs, increasing
the workload of the left heart.
• (bounding peripheral pulses)
• DX-echo /ultrasound
Diagnostic Tests
pda clip
•Echocardiogram.
•Chest X-ray
•Electrocardiogram
•Cardiac catheterization
Clinical Manifestations and Treatment
•Small PDA’s asymptomatic
•Large PDA’s signs of HF(e.g, failure to thrive, poor
feeding, tachypnea, dyspnea with feeding and
tachycardia), bounding peripheral pulses
•Machine like murmur in the left upper sternal border
•Treatment Options:
• PDA can sometimes be closed with using a
prostaglandin synthesis inhibitor
• indomethacin or ibuprofen(good for premies,
ineffective on full term)
• Large PDA-surgical ligation, various catheter
delivered occlusion devices
Acyanotc defects that obstruct flow:
Coarctation of the aorta
aortic stenosis
pulmonary stenosis
Coarctation of the aorta
• Coarctation of the aorta is a birth defect in which a
part of the aorta is narrower than usual.
• ¼ lived a normal life
• ¼ died from rupture of the aorta
• ¼ died from bacterial endocarditis
• ¼ died from hypertensive state
• Other defects seen with CoA-bicuspid aortic valve and
a VSD
DX
• Suspected when you are
unable to feel pulses in the
groin or the legs
• Dx made with
echocardiography,
arteriography, CT, MRI and
CXR
Coarctation of the aorta
90% juxta-ductal-(so keep the DA patent)
management
•To improve ventricular function and restore blood flow
to the lower body
•Open the ductus arteriosus with PGE-1 to allow blood
flow beyond the coarctation
• Surgical resection of the narrowed area with reanastmosis of the 2
ends together.
• Sometimes a subclavian flap aortoplasty
• Older children with less severe symptoms- planned electively with a
balloon angioplasty with stenting 20% of newborns will have restenosis
• Post-op Tx of HTN – due to high circulating levels of renin.
•If left untreated COA can lead to myocardial
ischemia, CVA and CHF.
•Life span is reduced to less than 40 yrs
Aortic stenosis
• The most common abnormality – the aortic valve has only two
leaflets, which are thicken and less pliable than normal.
(sometimes slightly fused together)
• This increases LV workload
• This deformity may not cause any problems until adulthood, at
which time the valve may begin to narrow or leak and may
need to be repaired or replaced.
• Clinical Manifestations
Pts with mild aortic valvular stenosis are usually
asymptomatic and in normal health
Severe aortic stenosis-develop heart failure within the first
few days of life and require immediate treatment
DX- a heart murmur(the most common sign) (the usual) Echo,
ultasound, CXR, aortography, EKG(LV strain)
TX – Mild stenosis no TX, most commonly used procedure is a
balloon dilation valvuloplasty(if there is a bicuspid valve with mild
fusion)
More complex valves with Ca++ deposits-surgical aortic
valve replacement
Pulmonary Stenosis
• Problems with the pulmonary
valve include:
A valve that has one or two
leaflets instead of three
A valve that has leaflets that are
fused together
• A valve that has thick leaflets that
do not open all the way
• (similar to AORTIC STENOSIS)
• Mild pulmonary stenosis may not cause any symptoms
• Problems occur when stenosis is moderate to severe including:
Increased RV workload and hypertrophy.
• Blood starts backing up into RA, symptoms include:
• Tachypnea, dyspnea, fatigue, tachycardia,
• swelling in the feet, ankles, face and/or abdomen.
Dx and tx similar to aortic stenosis
DX- a heart murmur(the most common sign)
Echo, ultasound, CXR, pulmonary arteriography, EKG(RV
strain)
TX – Mild stenosis no TX, most commonly used procedure is a
balloon dilation valvuloplasty(if there is a bicuspid valve with
mild fusion)
More complex deformed valve-surgical aortic valve
replacement
Cyanotic CHD with decreased pulmonary blood
flow
•Tetralogy of Fallot (TOF)
•Tricusid Atresia
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977,
1973, 1969 by Mosby, an imprint of Elsevier Inc.
58
• Tetralogy of Fallot:
• Pulmonary stenosis(limits blood flow to lung), VSD,
dextroposition(overriding) aorta, RV hypertrophy. These
allow oxygen poor blood to be pumped out the aorta
• Timing of surgical repair dependent on case
• If O2 levels are critical after birth PGE-1 is given to keep DA
open providing additional blood flow to the lungs.
•TET spell-hypercyanotic spells-increased
cyanosis, increased respiratory distress,
hypercapnia and syncope
•Chest radiograph shows “boot-shaped’ heart
TET spell
TOF-boot shaped heart
• DX-cyanotic, systolic ejection murmur, Echo,
ultrasound, CXR.
• TX-PGE, correct hypoxemia and acidosis, MV and
COMPLEX SURGERY-(patch VSD, enlarge RV outflow)
• Complete occlusion
of the
Tricuspid
atresia
tricuspid valve and a hypoplastic
RV
• Blood cannot flow from RA to RV
so circulation is maintained
through an ASD
• A VSD is also present allowing a
small amount of blood to be
directed into the RV and pulm
circulation
• A PDA is usually present
• Cyanosis is always present at
birth
•DX- presence of a heart murmur, echo,
ultrasound, ekg and CXR
•TX – keep PDA open to improve blood flow
to the lungs or body, correct hypoxemia, MV
and VERY COMPLEX surgery
Cyanotic CHD with Increased pulmonary
blood flow
• Truncus Arteriosus-failure of embryonic
truncus arteriosus to separate into the
aorta and PA.
• One great vessel leaving ventricles,
containg only one valve(truncal
valve)overlies a VSD
• Pulmonary and systemic blood mix and
circulate throughout the body resulting in
cyanosis.
• Tx-ventilatory support and surgical tx
separating the common vessels and
closing the VSD
Cyanotic CHD with Increased
pulmonary blood flow
• Hypoplastic Left Heart Syndrome(HLHS)
• Most structures of the left heart are small
and underdeveloped.
• Aortic and mitral valve stenosis or atresia.
• Hypoplasia of ascending aorta, (COA)
• Blood flow to LV severely compromised,
PDA supplies systemic circ and an ASD to
allow pulm venous blood to flow into RA
• An infant with HLHS will be cyanotic,
hypotensive and will not live long
without surgical intervention
• Pre-op management
• Intubation and MV, inotropic support
• Increase PVR(pulm vasoconstriction) by
decreasing FiO2(use N2) or inducing
resp acidosis
• PGE to keep PDA open(supplies
systemic circulation)
• TX- 3 staged complex surgery or heart
transplant
Cyanotic defects with variable blood flow
• Transposition of great
arteries(TGA)
• Manifests as moderate to
severe cyanosis at birth
• Some form of
communication(PDA, ASD,
VSD) must exist between the
two circulations for mixing of
blood to occur and allow
oxygenated blood to the
tissues
TGA
• Emergency atrial septostomy
relieves distress
• Perform arterial switch
operation at 2–3 weeks of life
and move coronary arteries to
the new aorta
• Chest radiograph shows “eggshaped” (egg on a stick) heart
Atrioventricular septal defect-av canal
• Accounts for 5% of all CHD
• Most common in Down syndrome
• Single valve between the atria
and ventricles