ms1 congenital heart dse

8/8/2019 MS1 Congenital Heart Dse

1/16

NCM 102 MS1

CONGENITAL HEART DISORDERS


STRUCTURE AND FUNCTION OF THE HEART (Anatomy & Physiology)A. Structure:I. Heart - composed of 4 chamberswith a septum in between the right and left chambers.

1. Right atrium - upper chamber2. Left atrium - upper chamber

3. Right ventricle - lower chamber4. Left ventricle - lower chamber

II. Great vessels 1. Arteries - coronary, aorta, brachiocephalic, subclavian and pulmonary.

2. Veins - IVC, SVC, and pulmonary.

III. 3 Tissue layers of the heart1. Myocardium2. Endocardium3. Pericardium - has 2 layers:

a. Serous pericardium, parietal layer

b. Serous pericardium, visceral layer*Pericardial space - space between the 2 pericardial layers which contains pericardial fluid to

allow frictionlessmovement of the heart muscles.

IV. Heart valves (4) 1. Pulmonic valve

2. Aortic valve3. Mitral valve4. Tricuspid valve

V. Electrical conduction system

1. Sinoatrial (SA) node2. Atrioventricular (AV) node3. Atrioventricular bundle (bundle of His)4. Purkinje fibers

B. Function:The CV systems basic function is to pump oxygenated blood to tissues and toremove metabolic waste products from the tissues.I. Cardiac cycle - involves sequential contraction (systole) and relaxation (diastole) of theatria and ventricles.

Atrial contraction - will eject blood into the ventricles

Atrial relaxation

Ventricular contraction - will eject blood into lungs via the pulmonary artery and

to the systemic circulation via the aorta

Blood returns to the right atrium completing the cycle- from the systemic circulation via SVC and IVC- from the pulmonary circulation via Pulmonary artery

1


2/16

NCM 102 MS1


II. Cardiac output (CO) - is the volume of blood ejected by the ventricles during a given period(1 minute)

- varies as the metabolic needs of body tissues changes (ex: exercise)- CO = Heart rate x Stroke volume

C. Fetal and Postnatal circulation1. Fetal heart development - begins during the first month of gestation; at 21 days AOG beginsbeating and blood starts

to circulate.2. Between 2nd and 7th weeks AOG -the primitive heart starts to develop the 4 chambers andgreat arteries.3. During gestation, the lungs are nonfunctional . Fetal oxygenation occurs via the placenta.4. Key structures in the fetal circulation include:

a. Foramen ovale - opening between the atria that allows blood to flow from the right directlyto the left atrium.

b. Ductus arteriosus - a conduit between the pulmonary artery and the aorta that shunts bloodaway from the

pulmonary circulation.5. Important circulatory changes during transition to extrauterine life:

a. Inspired O2 dilates pulmonary vessels, decreasing pulmonary vascular resistance and

increasing pulmonary bloodflow, which facilitates lung expansion.

b. Foramen ovale closes functionally soon after birth from compression of the atrial septum.

2


3/16

NCM 102 MS1


PHYSICAL ASSESSMENT

I. Health history - Description of symptoms including onset, duration, location and

precipitation.

- Cardinal s/sx like feeding problems, respiratory difficulties and chronic

fatigue.

- Prenatal risk factors like maternal use of medications, tobacco or alcohol.- Personal risk factors such as chromosomal abnormalities, prematurity,

infections.

- Family risk factors include congenital heart disease, M.I. before 55 years of

age or sudden

death of unknown cause.

II. Physical examination

1. Vital signs - blood pressure, cardiac rate, respiratory rate, temperature

3


4/16

NCM 102 MS1


2. Inspection - cyanosis, periorbital/peripheral edema, engorged neck veins, clubbing of fingers

or toes,

Abdominal distention.

3. Palpation - precordium for PMI, thrills, lift and heaves.

- abdomen for hepatomegally and splenomegally.

- extremities for pitting edema.

4. Auscultation - anterior chest for heart sounds and murmurs.

- posterior chest for adventitious lung sounds.

III. Diagnostic Procedures

1. Complete blood count (CBC) - to assess a compensatory increase in Hemoglobin and

hematocrit levels and

erythrocyte count (polycythemia).

2. Pulse oximetry - identifies the childs O2 saturation level.

3. Coagulation studies - to identify abnormalities in hemostasis (decreased platelet, clotting

factors)

4. ECG - evaluation of cardiac function

5. CXR - heart size and distribution of pulmonary blood flow6. Echocardiography - more detailed assessment of heart structure and function

7. Cardiac catheterization - assessment of anatomic abnormalities

8. Angiography - radiographic visualization of the heart and its blood vessels with a contrast

medium

IV. Therapeutic Management

Medications used to treat cardiovascular disorders

1. Potent vasopressors - dopamine, dobutamine, epinephrine and isoproterenol

2. ACE Inhibitors - enalapril, captopril

3. Beta-adrenergic blockers - propranolol

4. Diuretics - furosemide, hydrochlorothiazide

5. Antiarrhythmics - digoxin

6. Antibiotics - penicillin, sulfadiazine

7. Anti-inflammatory - aspirin, corticosteroids

V. Nursing Management

1. Promote adequate cardiac output and oxygenation

2. Promote adequate nutrition

3. Prevent infection

4. Provide preoperative and postoperative care

Congenital Heart Diseases (CHD)Overview:

1. CHDs are structural defects of the heart, great vessels or both that are present from birth.

2. Incidence - 5 to 8 / 1,000 live births.

3. Children with CHD are more likely to have associated defects such as TEF and chromosomal

defects.

4. CHDs are divided into 2 major classifications each with different variations and defects.

Classification:

I. Acyanotic Defects

4


5/16

NCM 102 MS1


1. Increased Pulmonary blood flow

a. ASD Atrial septal defect

b. VSD Ventricular septal defect

c. PDA Patent ductus arteriosus

d. AVC Atrioventricular canal defect

2. Obstruction to blood flow from ventricles (Obstructive defects)

a. CoA Coarctation of the aorta

b. AS Aortic stenosisc. PS Pulmonic stenosis

II.Cyanotic Defects

1. Decreased Pulmonary blood flow

a. TOF Tetralogy of Fallot

b. Tricuspid atresia

2. Mixed blood flow (Mixed defects)

a. TGA/TGV Transposition of the great arteries/vessels

b. TAPVC Total anomalous pulmonary venous connection

c. TA Truncus arteriosusd. HLHS Hypoplastic left heart syndrome

Etiology:

1. More than 90% of CHD cases - cause is unknown

2. Factors associated with increased incidence of CHD include:

- fetal and maternal infection during the 1st trimester, especially rubella (German measles).

- maternal alcoholism

- maternal use of other drugs with teratogenic effects

- maternal age >40 y.o.

- maternal dietary deficiencies

- maternal insulin-dependent induced diabetes

- sibling with CHD

- parent with CHD

- chromosomal abnormality such as Down syndrome

ASD Atrial Septal Defect: Abnormal opening between the 2 atria, allowing blood from the

higher pressure left atrium

into the low pressure right atrium resulting in ineffective pumpingof the heart, thus

increasing the risk of heart failure. Unknown cause.

5


6/16

NCM 102 MS1


There are 3 types:

1. ASD-2 or Ostium secundum - Most common type of ASD

- Opening occurs near center of septum between the right

and left atrium.- A variant of this type is called patent foramen ovale (PFO)

and is very small.

- Non-surgical treatment; maybe closed using devices

during cardiac catheterization.

Normal heart ASD-2

2. ASD-1 or Ostium primum - Next most common type, commonly occurs with Downs

syndrome.

- Opening occurs at the lower end of septum

- May be associated with a mitral valve defect known as

mitral valve cleft (a slit-like or

elongated hole at one of the leaflets (anterior leaflet) that

form the mitral valve.

- May require repair or rarely MV replacement.

6


7/16

NCM 102 MS1


Normal heart ASD-1

3. Sinus venosus ASD - The least common,often has an abnormal pulmonary vein connection

associated with it.

- Four pulmonary veins, two from the right lung and two from the left

lung, normally return red

blood to the left atrium.

- A pulmonary vein from the right lung will be abnormally connectedto the right atrium instead

of the left atrium. This is called an anomalous pulmonary vein.

- Opening is near the junction of SVC (superior vena cava) & RA (right

atrium) or upper portion

of the atrial septum.

- Maybe associated with a partial anomalous pulmonary venous

connection.

- Treatment requires patch placement, so the anomalous right

pulmonary venous return is

directed to the left atrium.

Clinical Manifestations: Assymptomatic

Fatigue on exertion

May develop CHF (congestive heart failure)

Presence of characteristic murmur

Surgical Treatment: Surgical Dacron patch closure of moderate to large defects similar to

closure of VSDs.

1. The surgical approach to the atrial septal defect is somewhat dependent upon its location.

2. Open repair with CPB (cardiopulmonary bypass) before school age (preschool or early school

age).

3. In general, three surgical approaches may be undertaken:

7


8/16

NCM 102 MS1


>median sternotomy (midline sternal-splitting incision)

>right thoracotomy (going between the ribs on the right side)

>submammary (under the breast tissue on the right front of the chest)

Complications: Physical underdevelopment

Respiratory infections

Heart failure

Atrial arrhythmias

Mitral valve prolapse.

VSD Ventricular Septal Defect: Most common CHD.

Abnormal opening between the right and left ventricles.

Frequently associated with other defects: PS, TGV,PDA,

COA and other atrial defects.

Spontaneous closure occurs in about 20-60% of cases

during the 1st year of life in

children having small or moderate defects.

The septum is a wall that separates the heart's left and right sides. Septal defects are sometimes

called a "hole" in the heart. A defect between the heart's two lower chambers (the ventricles) is

called a ventricular septal defect (VSD).

Pathophysiology:

When there is a large opening between the ventricles,

A large amount of oxygen-rich (red) blood from the heart's left side is forced through the defect

into the right side.

Then it's pumped back to the lungs, even though it's already been refreshed with oxygen.

This is inefficient, because already-oxygenated blood displaces blood that needs oxygen.

This means the heart, which must pump more blood, may enlarge from the added work.

High blood pressure may occur in the lungs' blood vessels because more blood is there.

Over time, this increased pulmonary hypertension may permanently damage the blood vessel

walls.

8


9/16

NCM 102 MS1


Clinical Manifestations: CHF (congestive heart failure) is common

Presence of a characteristic murmur

Risk for Bacterial endocarditis and Pulmonary vascular

obstructive disease.

Eisenmenger syndrome may develop in severe cases.

Surgical Treatment:

1. Palliative Pulmonary artery banding to decrease pulmonary blood flow. Common

approach in the past.2. Complete repair (procedure of choice) Performed via cardiopulmonary bypass. The repair

is generally approached

thru the right atrium and tricuspid valve. Post-op complications include residual VSD and

conduction disturbances.

a. Small defect repaired with a purse-string approach.

b. Large defect usually require a knitted Dacron patch sewn over the opening.

Nonsurgical treatment:

Device closure during cardiac catheterization has a high operative risk.

PDA Patent Ductus Arteriosus: Failure of the fetal ductus arteriosus (artery connecting the

aorta and pulmonary

artery) to close within the first weeks of life.

The continued patency of this vessel allows blood to flow

from the higher pressure

aorta to the lower pressure pulmonary artery, causing a

left-to-right shunt.

9


10/16

NCM 102 MS1


Clinical Manifestations: May be assymptomatic or may show signs ofCHF.

Characteristic machinery-like murmur .

Widened pulse pressure and bounding pulse. Risk for bacterial endocarditis and pulmonary vascular

obstructive disease.

Medical Management: Indomethacin (prostaglandin inhibitor)

Surgical Management: Surgical division or ligation of the patent vessel via a left thoracotomy.

Visual-assisted thoracoscopic surgery (VATS) a newer technique

that uses a thoracoscope

and instruments placed thru 3 small incisions to place a clip on the

ductus.

Nonsurgical treatment: Use of coils to occlude the PDA during catheterization.

AVC Atrioventricular Canal Defect: Incomplete fusion of endocardial cushions.

Consists of a low atrial septal defect that is continuous

with a high ventricular

septal defect and clefts of the mitral and tricuspid

valves, creating a large central

atrioventricular (AV) valve that allows blood to flow

between all 4 chambers of the

heart. It is the most common defect in children with

Down syndrome.

Clinical Manifestations: Moderate to severe CHF

Characteristic murmur

Mild cyanosis that increases with crying

High risk for developing pulmonary vascular obstructive disease

Surgical Treatment:

1. Palliative Pulmonary artery banding

2. Complete repair Patch closure of septal defects and reconstruction of AV valve tissue.

If MV defect is severe,

10


11/16

NCM 102 MS1


a valve replacementmay be needed.

COA Coarctation of the Aorta: Localized narrowing near the insertion of the ductusarteriosus, resulting in:

1. increased pressure proximal to the defect (head & upper

extremities)

2. decreased pressure distal to the obstruction (body &

lower extremities)

There are 3 types of CoA according to location:

a. Preductal - proximal to the insertion of the ductus

arteriosus

b. Postductal - distal to the ductus arteriosus

c. Juxtaductal - at the insertion of the ductus arteriosus

11


12/16

NCM 102 MS1


Clinical Manifestations: High BP and bounding pulses in armsWeak or absent femoral pulsesCool lower extremities with lower BPSigns of CHF in infantsRisk for HPN, ruptured aorta, aortic aneurysm or stroke

Surgical Treatment:1. Resection of the coarcted portion with end-to-end anastomosis of the aorta2. Enlargement of the constricted section using a graft of prosthetic material or a portion of

the left subclavian artery.3. Percutaneous balloon angioplasty effective for residual post-op coarctation

gradients.Note: Because the defect is outside the heart and pericardium, CPB is not required and athoracotomy incision is used.

Post-op HPN > 160mmHG treat with I.V. Na Nitroprusside or Amrinone followed byoral medications such as

captopril, hydralazine and/or propranolol.

Elective surgery within the first 2 years of life is advisedNonsurgical Treatment: Balloon angioplasty has a high restenosis rate in infants


13/16

NCM 102 MS1


1. Infants with severe defectsa. Decreased cardiac output with faint pulsesb. Hypotensionc. Tachycardiad. Poor feeding

2. Childrena. Exercise intoleranceb. Chest pain and dizziness when standing for a long period

3. Characteristic murmur4. Risk for bacterial endocarditis, coronary insufficiency and ventricular dysfunction

PS Pulmonic Stenosis: Narrowing at the entrance of the pulmonary artery.Resistance to blood flow causes RVH and decreased pulmonary

blood flow.

Clinical Manifestations: May be assymptomatic

Mild cyanosisCHF, murmur

Cardiomegally on CXRSurgical treatment:

1. Infants Brockprocedure or transventricular (closed) valvotomy 2. Children Pulmonary valvotomywith CPBNonsurgical treatment: Balloon angioplastyin cath.lab.

TOF Tetralogy of Fallot:The classic form includes four defects:1. VSD2. PS3. Overriding aorta

13


14/16

NCM 102 MS1


4. RVHClinical Manifestations:1. Infants acute episodes of hypercyanosis and hypoxia (blue/tet spells). Knee-chestposition. Characteristic murmur is

present.2. Children clubbing of fingers; squatting (serves to decrease the return of poorlyoxygenated blood from the lower

extremities and to increase systemic vascular resistance which increases

pulmonary blood flow and easesrespiratory effort) and poor growth.

Surgical treatment:1. Palliative shunt for infants who cannot undergo primary repair. Blalock-Taussig or B-TShuntis the preferred

procedure which provides blood flow to the pulmonary arteries from the left or rightsubclavian artery.2. Complete repair performed in the first year of life. It involves closure of the VSD andresection of the infundibular

stenosis, with a pericardial patch to enlarge the right ventricular outflow tract. This requires amedian sternotomy

and cardiopulmonary bypass.

Tricuspid Atresia: Failure of the tricuspid valve to develop.There is no communication between the RA and RV. It is often associated

with PS and TGV.There is complete mixing of unoxygenated and oxygenated blood in the left

side of the heart,resultingin systemic desaturation and pulmonary obstruction causing decreased

pulmonary blood flow.Patients are at risk of bacterial endocarditis , brain abscess and stroke

Clinical Manifestations:1. Newborn cyanosis, tachycardia and dyspnea2. Children chronic hypoxemia with clubbing

Surgical Treatment:1. Palliative placement of a shunt (Pulmonary-to-systemic artery anastomosis)2. Pulmonary artery banding to lessen blood flow to the lungs3. Bidirectional Glenn Shunt (Cavopulmonary anastomosis) performed at 6-9 months as a 2nd

stage.4. Modified Fontan procedure separates oxygenated and unoxygenated blood inside the heartand eliminates excess

volume load on the ventricle but does not restore normal anatomy or hemodynamics.5. Complete Fontan procedure conduit between right atrium and pulmonary artery.

Note: Absence of a tricuspid valve is incompatible with life unless there is presence of ASD, VSD,or PDA.

TGA/TGV Transposition of the Great Arteries/Vessels: The pulmonary artery leaves theleft ventricle and the aorta

14


15/16

NCM 102 MS1


exits from the right ventriclewith no communication between

the systemic and pulmonarycirculations.

Therapeutic Management: To provide intracardiac mixing administer I.V. PGE1 (ProstaglandinE-1).

Rashkind procedure (Balloon atrial septostomy) may be done

during cardiac catheterizationto increase mixing and maintain cardiac output for a longer

period.

Surgical treatment:1. Arterial switch procedure done during 1st week of life, to reestablish normal circulation withthe left ventricle acting as the systemic pump.2. Intraarterial baffle repairs done in the 1st year of life using the Senning and Mustardprocedures.

a. Senning procedure - diverts venous blood to MV and pulmonary venous blood to thetricuspid valve using the

patients atrial septum.

b. Mustard procedure - same as Sennings but a prosthetic is used instead of the patientsatrial septum.3. Rastelli procedure operative choice in infants with TGA, VSD and severe PS. Involves closureof the VSD with a baffle

directing left ventricular blood through the VSD into the aorta. The pulmonic valve is thenclosed and a conduit is

placed from the right ventricle to the pulmonary artery creating a physiologically normalcirculation. Disadvantage of

procedure is that it requires multiple conduit replacement as the child grows.

TAPVC Total Anomalous Pulmonary Venous Connection: Rare defect.Characterized by failure of

pulmonary veins to join the leftatrium.Instead, the pulmonary veins

are abnormally connected tothe systemic venous circuit

via the right atrium or variousveins draining toward the

right atrium such as the SVC.Clinical Manifestations: Cyanosis and CHFSurgical Treatment: Corrective repair in early infancy

TA Truncus Arteriosus: Single vessel that overrides both ventricles.This is due to the failure of normal septation and division of the

embryonic bulbar trunk intothe pulmonary artery and the aorta.

Clinical Manifestations: Moderate to severe CHFCyanosisPoor growthActivity intoleranceMurmur

15


16/16

NCM 102 MS1


Risk of brain abscess.

Surgical Treatment: Modified Rastelli Procedure done in the 1st few months of life. Closure ofVSD so TA receives outflow from LV, excision of pulmonary artery from aorta and attach it to theRV by means of homograft.

HLHS Hypoplastic Left Heart Syndrome: Underdevelopment of left side of the heart

resulting in a hypoplastic leftventricle and aortic atresia.Most blood from the left atrium flows across

the patent foramen ovale tothe right atrium, to the right ventricle, and

out the pulmonary artery.The descending aorta receives blood from

the patent ductus arteriosussupplying systemic blood flow.

Clinical Manifestations: CyanosisCHFUsually fatal in the 1st month of life without intervention.

Therapeutic Management: Prostaglandin-E1 infusion (PGE-1)

Surgical Treatment: Several-staged approach.1. First stage: Norwood procedure Anastomosis of the main pulmonary artery to the aorta tocreate a new aorta, shunt

placement and creation of a large ASD.2. Second stage: Bidirectional Glenn Shunt done at 6-9 months of age to relieve cyanosis andto reduce volume load on

the right ventricle.3. Third stage: Modified Fontan procedure to separate oxygenated from unoxygenated bloodand to eliminate excess

volume load on ventricles.

Heart transplantation best option for newborns.

ms1 congenital heart dse

Documents