11 19 2014 Congenital heart Defects

Question 1

Formation of heart tube?

Answer 1

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

Question 2

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

Answer 2

membranous intraventricular septum – Atrioventricular canal = tricuspid and mitral orfices

Question 3

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

Answer 3

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

Question 4

Fetal blood circulation:

Answer 4

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

Question 5

What happens after birth in infant circulation?

Answer 5

• 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

Question 6

Cyanosis

Answer 6

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

Question 7

Atrial Septal Defects anatomical cause:

Answer 7

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

Question 8

Physiology of Atrial Septal Defects

Answer 8

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

Question 9

Clinical presentations of Atrial Septal Defects

Answer 9

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)

Question 10

Physical findings on exam for Atrial Septal Defects (ASD)

Answer 10

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)

Question 11

Treatment for ASD?

Answer 11

Closure in early infancy

Question 12

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

Answer 12

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

Question 13

Ventricular Septum defect ( Anatomy)

Answer 13

Abnormal opening in the inter-ventricular septum Membranous *

Question 14

VSD physiology

Answer 14

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

Question 15

VSD clinical findings (symptoms)

Answer 15

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

Question 16

Physical findings on exam on VSD:

AND TREATMENT of VSD

Answer 16

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

Question 17

Anatomy of Patent Ductus Arteriosus (PDA)?

Physiology– including 3 major causes?

Answer 17

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

Question 18

Clinical findings on someone with PDA?

Answer 18

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)

Question 19

Anatomy of Congenital Aortic Stenosis

Physiology?

Answer 19

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)

Question 20

Clinical symptoms of congenital aortic stenosis?

Answer 20

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

Older children/adult – asymptomatic

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

Question 21

Clinical findings for chronic aortic stenosis?

Answer 21

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

Question 22

Treatment for Congenital Aortic stenosis?

Answer 22

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

SURGERY may be needed later.

Question 23

Pulmonic Stenosis:

Anatomy and physiology

Answer 23

Congenital fusion of the pulmonic valve commissures

PHysiolgoy:

Impairment of RV outflow = increase in RV pressure

= RVH

Question 24

Clinical symptoms of pulmonic stenosis?

mild vs. severe:

Answer 24

Mild/moderate = asymptomatic

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

Question 25

Physical findings of pulmonic Stenosis? - CXR/ ECG findings? - Treatment?

Answer 25

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

Question 26

Coartation of Aorta: anatomy and physiology?

Answer 26

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

Question 27

Clinical symptoms in people with coartation of aorta: - infant and severe - less severe--childhood? - prognosis in asymtomatic patients?

Answer 27

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

Question 28

Physical findings from examination of coartation of aorta: -CXR and echo findings?

Answer 28

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

Question 29

Treatment of coarctation of aorta - neonates - if less severe

Answer 29

neonates: prostaglandin infusion to maintain patency Less severe = elective repair via surgery or percutaneous balloon dilatation

Question 30

Tetralogy of Fallot Anatomy:

Answer 30

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)

Question 31

Physiology behind tetralogy of Fallot

Answer 31

R--\> left shunt increase resistance due to pulmonary stenosis = deoxygenated blood returning from systemic veins (RV) goes to LV to systemic arteries

Question 32

Clinical presentation of Tetralogy of Fallot:

Answer 32

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)

Question 33

Physical exam findings in Tetralogy of Fallot - CXR - ECG

Answer 33

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

Question 34

Treatment of Tetralogy of Fallot?

Answer 34

Surgical closure of VSD and enlargement of subpulmonary infundibulum -replace Pulm Valve as adults

Question 35

Anatomy and physiology behind transposition of Great vessels?

Answer 35

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

Question 36

Clinical presentation of baby with transposition of great vessels?

Answer 36

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

Question 37

Physical exam presentation and Treatment of Transposition of great vessels

Answer 37

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

Question 38

Eisenman syndrome: Physiology Clinical findings Physical exam Tx:

Answer 38

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