11 19 2014 Congenital heart Defects Flashcards Preview

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


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

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


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


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


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



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


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


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


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)


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)


Treatment for ASD?

Closure in early infancy


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


Ventricular Septum defect ( Anatomy)

Abnormal opening in the inter-ventricular septum Membranous *


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


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


Physical findings on exam on 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


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



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)


Anatomy of Congenital Aortic Stenosis



Males> females



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)


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


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


Treatment for Congenital Aortic stenosis?

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

SURGERY may be needed later.


Pulmonic Stenosis:


Anatomy and physiology

Congenital fusion of the pulmonic valve commissures



Impairment of RV outflow = increase in RV pressure



Clinical symptoms of pulmonic stenosis?

mild vs. severe:

Mild/moderate = asymptomatic


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


Physical findings of pulmonic Stenosis?

- CXR/ ECG findings?


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


Coartation of Aorta: anatomy and physiology?

Preductal or postductal discrete narrowing of aortic lumen.

Usually associated with bicuspid valve



decrease anterograde flow = Increase afterload = increase LVP

=  LVH


Dilation of intercostal artiers that bypass site of coarctation

= costal notching


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


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


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


Treatment of coarctation of aorta


- if less severe

neonates: prostaglandin infusion to maintain patency


Less severe = elective repair via surgery or percutaneous balloon dilatation


Tetralogy of Fallot


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)