congenital heart disease I Flashcards by Tiffany Pointon

Risk factors for congenital heart disease

maternal diabetes, family history of cardiac defect in first degree relative

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Patent ductus arteriosus is what kind of a shunt? Why?

Left to right (from aorta to pulmonary artery) b/c aortic resistance and pressure are greater than pulmonary resistance and pressure

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Physical exam of patent ductus arteriosus w/left to right flow

wide pulse pressure,Bounding pulses (palpable palmar pulses), Increased work of breathing, Hyperactive precordium, Murmur- variable…

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Describe the murmur of a PDA

Continuous or machinery sounding murmur along the left upper sternal border, with a diastolic rumble if shunt is large. Also, accentuated P2 if pulmonary hypertension

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Chest X ray of PDA

nIncreased pulmonary vascular markings, enlarged left atrium and left ventricle if large

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Mangement of PDA

Symptomatic neonate: COX inhibitors (NSAIDS) or surgical ligation . Symptomatic older child: percutaneous occlusion. Asymptomatic older child: percutaneous closure if murmur, no intervention if silent

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Why are COX inhibitors used in PDA

PDA stays open due to prostaglandins (vasoactive agents) keeping the vessel open. COX inhibitors block conversion of arachidonic acid to prostaglandins. Wait until 48 hrs of life to allow spontaneous closures.

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Complications of PDA

Pulmonary veno-occlusive disease (pulmonary HTN), Eisenmenger disease, increased risk of bacterial endocarditis

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What is Eisenmengers disease

The left to right shunt causes increased pulmonary blood flow >muscularization of pulmonary arterioles > pulmonary HTN > increased pressure in the right side of the heart >shunt reversal (R to L) > cyanosis and clubbing > death or Heart/lung transplant

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Describe embryology of atrial septum

Day 28-42: The septum primum grows down btw atria, leaving the ostium primum and secundum holes. Then the septum secundum grows down to the right of the septum primum. This atrial septum fuses with the endocardial cushions which are involved in ventricular septation

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What is the most common type of atrial septal defect

Secundum ASD: Ostium secundum hole in the septum primum is too large, OR inadequate development of septum secundum

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Describe blood flow in ASD

left to right shunt b/c RV has higher compliance than LV, and systemic vascular resistance is higher than pulmonary vascular resitance

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When does ASD usually present?

Rarely presents in infancy b/c LV and RV myocardium are similar right after birth and they have similar inflow resistance > minimal atrial level shunt > minimal symptoms. As pulmonary vascular resistance falls and RV wall thins, left to right shunting increases
Rarely presents in infancy b/c LV and RV myocardium are similar right after birth and they have similar inflow resistance > minimal atrial level shunt > minimal symptoms. As pulmonary vascular resistance falls and RV wall thins, left to right shunting increases
Rarely presents in infancy b/c LV and RV myocardium are similar right after birth and they have similar inflow resistance > minimal atrial level shunt > minimal symptoms. As pulmonary vascular resistance falls and RV wall thins, left to right shunting increases

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Physical exam of atrial septal defect

May have normal exam if small. If large, May present in infancy with increased respiratory rate, sweating with feeds, but may be asymptomatic. Liver 2-3 cm below right costal margin. 2-3/6 systolic ejection murmur at upper left sternal border ± diastolic rumble at lower left sternal border. Second heart sound is widely split
May have normal exam if small. If large, May present in infancy with increased respiratory rate, sweating with feeds, but may be asymptomatic. Liver 2-3 cm below right costal margin. 2-3/6 systolic ejection murmur at upper left sternal border ± diastolic rumble at lower left sternal border. Second heart sound is widely split
May have normal exam if small. If large, May present in infancy with increased respiratory rate, sweating with feeds, but may be asymptomatic. Liver 2-3 cm below right costal margin. 2-3/6 systolic ejection murmur at upper left sternal border ± diastolic rumble at lower left sternal border. Second heart sound is widely split

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Explain the murmur found in ASD

Systolic ejection murmur Secondary to excessive blood flow across the pulmonary valve. Diastolic rumble due to excessive blood flow in diastole across the tricuspid valve

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Explain the widely split S2 in ASD

RV volume overload occurs due to ASD, and delayed RV emptying causes a wide splitting of S2 in all phases of respiration

Atrial septal defect diagnosis

Chest Xray (variable heart size, pulmonary artery enlargement, pulmonary vascular markings) and Echo (size/location of defect, magnitude of shunt)

ASD natural history

Undetected in childhood. Long term risks: pulmonary vascular disease (from pulmonary HTN), atrial arrhythmias ( due to atrial enlargemet), cardiac failure (right heart failure)

Why does pulmonary vascular disease develop in ASD

High pulmonary blood flow results in increased pulmonary vascular resistance (PVR)

Treatment of ASD

In infants: diuretics can relieve breathlessness. In everyone else, close the hole w/ surgery or percutaneous device closure

Embryology of ventricular septation

Days 28-42: The intraventricular septum grows towards the base of the heart as the ventricular outpouchings develop. At the same time, 4 endocardial cushions appear which form a right and left atrioventricular canal

What do each of the endocardial cushions become?

Right: part of tricuspid valve. Left: post leaflet of mitral valve. Superior: part of mitral valve Inferior: part of tricuspid and mitral, membranous portion of interventricular septum

Most common form of ventricular septal defect. Less common form of VSD

perimembranous VSD is most common: Deficiency or lack of the Membranous portion of the interventricular septum. Muscular VSD is less common: deficiency in the muscular portion of interventricular septum

Flow of blood in VSD

PVR is less than SVR, so left to right shunt occurs. Pulmonary blood flow returning to the left atrium is increased >Increased end-diastolic volume of the LV >
Muscle fiber length is increased >Frank-Starling mechanism results in increased LV contractility > Increased LV output
PVR is less than SVR, so left to right shunt occurs. Pulmonary blood flow returning to the left atrium is increased >Increased end-diastolic volume of the LV >
Muscle fiber length is increased >Frank-Starling mechanism results in increased LV contractility > Increased LV output

Clinical presentation of VSD

Asymptomatic until PVR falls after birth, even if defect is large. Large VSD: Respiratory distress and diaphoresis- especially noted with feeds, Failure to thrive. Small VSD: Tachypnea, diaphoresis usually mild or absent _x0002__x0000_Asymptomatic until PVR falls after birth, even if defect is large. Large VSD: Respiratory distress and diaphoresis- especially noted with feeds, Failure to thrive. Small VSD: Tachypnea, diaphoresis usually mild or absent _x0002__x0000_

Physical exam of VSD

Large VSD: Active precordium, Accentuated second heart sound, 2-3/6 harsh, holosystolic murmur loudest at LLSB, but can usually be heard throughout the chest, Diastolic murmur- secondary to increased flow across the mitral valve. Small VSD: Precordial activity usually normal, Normal second heart sound, 2-4/6 early systolic murmur,No diastolic murmur

What causes the murmur in VSD

Holosystolic murmur is due to flow across the defect- pressure difference btw LV and RV is large. Diastolic murmur- secondary to increased flow across the mitral valve.

Diagnosis of VSD

echo, ECG ( normal if small VSD, right axis deviation with increased RV and LV voltages due to hypertrophy if large VSD), CXR (cardiomegaly, increased lung vascularity)

Treatment of VSD

In infants, manage symptoms which include heart failure symptoms, pulmonary edema with diuretics. Surgical closure done if large defect with pulmonary vascular changes, persistent symptoms/poor growth, secondary complications (aortic regurg)

VSD natural history

Most small defects close spontaneously Many large defects decrease in sizeMost small defects close spontaneously Many large defects decrease in size

Tetralogy of Fallot

1.Right ventricular outflow tract obstruction 2. RV hypertrophy. 3. Dextraposition of aorta (aorta overrides the VSD). 4. Ventricular Septal Defect

Blood flow in tetralogy of fallot

VSD is large, so RV and LV pressures are equal. Pulmonary blood flow comes from RV output to pulmonary arteries and Ductus arteriosus flow (if present). If outflow obstruction is severe, most PBF is derived from the DA VSD is large, so RV and LV pressures are equal. Pulmonary blood flow comes from RV output to pulmonary arteries and Ductus arteriosus flow (if present). If outflow obstruction is severe, most PBF is derived from the DA

Sources of RV outflow obstruction in tetralogy

narrowing of infundibular region or stenosis of pulmonary valve

Compare blue tetralogy to pink tetralogy

Blue: R to L shunt if RV outflow resistance is higher than systemic vascular resistance > Cyanosis. Pink: L to R shunt if RV outflow resistance is less than systemic vascular resistance > No cyanosis

What are tet spells, exam fidings and treatment

Hypoxic or Hypercyanotic Spells that usually occur at 2-6 months of age. Precipitated by prolonged crying, anemia, dehydration or spontaneously. Exam: Blue, decreased murmur intensity and altered conciousness. Treatment: increase pulmonary blood flow by knee chest position(increases SVR) , Phenylephrine (increases SVR), morphine, volume expansion with IV fluids. Prevention: Beta blockers may decrease obstruction

Diagnosis of tetralogy of fallot

physical exam: Tachycardic and cyanotic if Blue Tet, Diaphoretic and tachypneic if Pink Tet. Precordial impulse displaced to the lower left sternal border > RV dominance. 2-3/6 short systolic murmur of pulmonary stenosis. ECG: right axis deviation and right ventricular hypertrophy

Management of tetralogy

Outpatient medical management possible in infants that have adequate saturations once the ductus is closed (propranolol for tet spell prevention, elective surgical repair at 2-4months). Ductal dependent PBF > maintain on Prostaglandin infusion (early surgical repair or palliation which creates a shunt btw the aorta and pulmonary artery)

Natural history of tetralogy

If RVOT obstruction is severe with ductal dependence, death at time of ductal closure. Otherwise, can survive into young adulthood: Cyanotic, clubbing of fingers, poorly developed dental enamel, bleeding tendencies, limited exercise tolerance (squat with exercise to increse SVR), arrhythmias