congenital heart disease I Flashcards
Risk factors for congenital heart disease
maternal diabetes, family history of cardiac defect in first degree relative
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
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…
wide pulse pressure,Bounding pulses (palpable palmar pulses), Increased work of breathing, Hyperactive precordium, Murmur- variable…
wide pulse pressure,Bounding pulses (palpable palmar pulses), Increased work of breathing, Hyperactive precordium, Murmur- variable…
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
Chest X ray of PDA
nIncreased pulmonary vascular markings, enlarged left atrium and left ventricle if large
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
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.
Complications of PDA
Pulmonary veno-occlusive disease (pulmonary HTN), Eisenmenger disease, increased risk of bacterial endocarditis
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
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
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
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
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
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
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
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
