11 19 2014 Congenital heart Defects Flashcards Preview

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Flashcards in 11 19 2014 Congenital heart Defects Deck (38):
1

Formation of heart tube?

mesodermal cells make Endocardial cushions which fuse ventrally to make one heart tube. The heart tube will eventually become the endocardium. splanchnic mesoderm will become the myocardium

2

What will the endocardial cushions eventually become (specific structures:)

membranous intraventricular septum -- Atrioventricular canal = tricuspid and mitral orfices

3

What cells make up the aorticopulmonary septum? What is the function of the aorticopulmonary septum?

5th week of gestation, neural crest derived mesenchymal cells proliferate. - 180 degree spiral - Divide truncus arterioles into Atrial cannals: pulmonic artery and aorta

4

Fetal blood circulation:

Umbilical cord Ductus venosus: bypass liver circulation IVC Goes into RA and two paths can be taken: 1. Foramen ovale to LV LV --> ascending aorta: coronary arteries, upper body and brain; descending aorta 2. Mix with blood from superior vena cava --> RV --> Pulmonary Artery --> Ductus Arteriosus ---> descending aorta From descending aorta Umbilical vein back to Placenta

5

What happens after birth in infant circulation?

- Lungs expand and 1. decrease pulmonary resistance via dilation of wall and therefore vessels 2. Vascular resistance in vessels of lungs dilate in response to rich O2 blood supply = Decreases RVP and increases LAP. LAP > RAP and foramen ovale is shut Ductus Arteriosus starts closing due to decrease in prostaglandin and increase O2 saturation

6

Cyanosis

blue-purple coloration of the skin and mucous membranes caused by an elevated blood concentration of deoxygenated Hb. Due to Right --> left shunting in congenital heart defects * bypassing lungs

7

Atrial Septal Defects anatomical cause:

Acyanotic: L--> R shunt Persistent opening in the intratrial septum after birth Direct communication between L. and R. A. Common site: ostium secundum

8

Physiology of Atrial Septal Defects

Oxygenated blood from LA →RA Volume overload of RA and RV. Eisenmenger syndrome may occur with increase RV compliance – if developed closure is contraindicated

9

Clinical presentations of Atrial Septal Defects

Most are asymptomatic (infant) If symptoms occur: dyspnea on exertion, fatigue, recurrent lower respiratory tract infections Adults: decreased stamina, palpitations (atrial tachy due to RA enlargement)

10

Physical findings on exam for Atrial Septal Defects (ASD)

Murmur in childhood/ adolescents (upper left systolic)

* murmur not common because pressure gradients are the same.

Systolic impulse along lower-left sternal border (RV heave)

S2 = widened, fixed pattern

RVH: CXR/ECG/Echocardiography

Catherization: RA O2 saturation >> SVC (usually they are the same)

11

Treatment for ASD?

Closure in early infancy

12

Anatomy and physiology of a Patent Foramen Ovale (PFO) What is it usually associated with?

not a true ASD = persistant opening of foramen ovale (persistence of fetal anatomy) Usually silent because it remains closed due to LAP> RAP HOWEVER it can become significant if RAP>LAP – ex. pulmonary hypertension Paradoxical emoblism: thrombus in systemic vein breaks loos : RA -> LA --> systemic arterial circulation

13

Ventricular Septum defect ( Anatomy)

Abnormal opening in the inter-ventricular septum Membranous *

14

VSD physiology

L→R shut - large shunt: volume overload in RV (not frequently), pulmonary circulation, LA, and LV = chamber dilation—systolic dysfunction can lead to pulm. Vascular disease as early as 2 yrs old. -pulm vas resistance = Eisenmenger syndrome

15

VSD clinical findings (symptoms)

Usually asymptomatic if small. Symptoms of heart failure Infants: tachypnea, poor feeding, failure to thrive, frequent lower respiratory tract infections Cyanosis/hypoxia and dyspnea (Eisenmenger syndrome) endocarditus

16

Physical findings on exam on VSD:

 

AND TREATMENT of VSD

Harsh holosystolic murmur best heard at left sternal border

*smaller = louder

 

CXR/ECG = Left sided enlargement

-R. enlargement when eisenmenger develops

-cyanosis and loud P2 closure (due to increase in Pul. vascular pressure)

 

 

Tx. Surgical or percutaneous closure

17

Anatomy of Patent Ductus Arteriosus (PDA)?

 

Physiology-- including 3 major causes?

Vessel that connects the left pulmonary artery to the decending aorta in fetal anatomy remains open.

Composed of smooth muscle (which usually reacts to O2 levels)

L --> R shunt that causes volume overload in pulmonary system, LA, LV and aorta

 

LV – dilate

* Left side of heart dilates

 

Desaturated blood to go to lower extremities.

 

-Rubella (1st trimester)

- prematurity

-born@ high altitued

 

18

Clinical findings on someone with PDA?

Early congestive heart failure, tachycardia, poor feeding, slow growth, recurrent lower respiratory

 

Moderate size lesion= fatigue, dyspnea, palpitations

 

Adult: Atrial fibrillation due to LA dilation

 

Turbulent flow = endocarditis (aka Endoarteritis)

19

Anatomy of Congenital Aortic Stenosis

 

Physiology?

Males> females

BICUSPID AORTIC VALVE

 

Valvular orifice is significantly narrowed

-eccentric stenotic opening

 

= increase LV P= LVH due to PRESSURE LOAD

(dilation of aorta)

 

-bicuspid valve becomes progressively fibrosed and calcified (stenosis)

20

Clinical symptoms of congenital aortic stenosis?

Severe –infants: tachycardia, tachypnea, failure to thrive, poor feeding

 

Older children/adult – asymptomatic

- But when severe = fatigue, exertion dyspnea, angina pectoris, and syncope

21

Clinical findings for chronic aortic stenosis?

Harsh crescendo-decrescendo systolic murmur best heard at base of <3 with radiation to the neck

 

Bicuspid = murmur is preceded by an ejection click.

 

Severe disease = paradoxical splitting of S2

 

CXR/ECG: enlarged heart with dilated aorta; LVH

22

Treatment for Congenital Aortic stenosis?

 Balloon valvuloplasty in infancy  * immediately!  but only in severe AS

SURGERY may be needed later.

23

Pulmonic Stenosis:

 

Anatomy and physiology

Congenital fusion of the pulmonic valve commissures

 

PHysiolgoy:

Impairment of RV outflow = increase in RV pressure

= RVH

24

Clinical symptoms of pulmonic stenosis?

mild vs. severe:

Mild/moderate = asymptomatic

 

Severe = dyspnea, exercise intolerance, decompensation, symptoms of right heart failure

25

Physical findings of pulmonic Stenosis?

- CXR/ ECG findings?

-Treatment?

Peripheral edema

JVP—prominent A-wave

Palpable liver/ abdominal fullness

RV heave over sternum

 

Loud late-peaking crescendo-decrescendo systolic ejection murmur heard at upper-left sternal border—associated with a palpable thrill

 

Widening of S2

 

Pulmonic valve click decreases with inspiration (push cusps into pulm. Artery= muffle sound

 

CXR/ECG = RVH ; echocardiogram = increased gradient across Pulm. Valve, elevated Rt. Side pressures, RVH

 

Tx: balloon valvuloplasty

26

Coartation of Aorta: anatomy and physiology?

Preductal or postductal discrete narrowing of aortic lumen.

Usually associated with bicuspid valve

 

Physiology:

decrease anterograde flow = Increase afterload = increase LVP

=  LVH

 

Dilation of intercostal artiers that bypass site of coarctation

= costal notching

27

Clinical symptoms in people with coartation of aorta:

-infant and severe

-less severe--childhood?

-prognosis in asymtomatic patients?

Infants: Severe coartation= differential cyanosis (LE are cyanotic)

 

Less severe: mild weakness or pain in the LE following exercise (claudication) and detected later in childhood due to HTN.

 

Asymptomatic = UE hypertension later in life

28

Physical findings from examination of coartation of aorta:

 

-CXR and echo findings?

Femoral pulses are weak/ delayed

 

Differential BP if UE are still getting enough blood (coartaction is in descending aorta)

 

CXR—notching on inferior surface of posterior ribs; if severe may see actually constriction of aorta

ECG—LVH

Definitive diagnosis: CT,  Doppler Echocardiography, MRI= imaging of aorta

29

Treatment of coarctation of aorta

-neonates

- if less severe

neonates: prostaglandin infusion to maintain patency

 

Less severe = elective repair via surgery or percutaneous balloon dilatation

30

Tetralogy of Fallot

Anatomy:

Abnormal anterior and cephalad displacement of infundibular portion of intraventricular septum

 

1. VSD

2. subvalvular Pulmonic stenosis

3. overriding aorta

4. RVH (due to pulmonic stenosis)

31

Physiology behind tetralogy of Fallot

R--> left shunt

 

increase resistance due to pulmonary stenosis = deoxygenated blood returning from systemic veins  (RV)  goes to LV to systemic arteries

32

Clinical presentation of Tetralogy of Fallot:

Dyspnea on exertion

 

“Spells” on exertion, feeding, crying (systemic vasodilation increased R --> L shunt)

- irritability, hypoxia,cyanosis

 

Squatting makes it better (increases systemic vascular resistance)

33

Physical exam findings in Tetralogy of Fallot

-CXR

-ECG

Mild cyanosis of lips, mucous membranes, digits

 

Clubbing of fingers and toes

 

Palpable heave along left sternal border

 

S2 is single

 

Pulmonic Systolic ejection murmur

 

CXR: “boot shaped heart”

ECG = RVH

34

Treatment of Tetralogy of Fallot?

Surgical closure of VSD and enlargement of subpulmonary infundibulum

-replace Pulm Valve as adults

35

Anatomy and physiology behind transposition of Great vessels?

Aorta arises from RV; Pulmonary artery arises from LV

-failure of aorticopulmonary septum to spiral in a normal fashion

 

Physiology:

Systemic and pulmonary circulations are in parallel vs. series

Some blood is necessary to maintain life – patent ductus arteriosis = viable in utero

36

Clinical presentation of baby with transposition of great vessels?

Appear blue

 

Cyanosis is apparent on first day of life and progresses rapidly as ductus arteriosis closes

37

Physical exam presentation and Treatment of Transposition of great vessels

Palpation of chest =  RV impulses at the lower sternal border

 

Tx.  Exogenous psotaglandins or surgery to maintain PDA open/ balloon catheter

* MEDICAL EMERGENCY

* Atrial switch operation

38

Eisenman syndrome:

Physiology 

Clinical findings

Physical exam 

Tx: 

Severe pulmonary vascular obstruction that results from chronic left-right shunting through a congenital cardiac defect

*reversal of original shunt

 

Clinical findings:

Hypoxemia, exertional dyspnea, fatigue, cyanosis

 

Physical Exam:

erythrocytosis (production of new blood cells) – try to increase Hb

prominent A-wave in JVP due to increase in R sided pressure.

Loud P2

 

Treatment:

Dual lung and heart transplant

* once condition develops, correction of original defect is contraindicated