Pediatric cardiology Flashcards
Left to right shunt lesion:
extra blood is displaced through a communication from the left to the right side of the heart; increased pulmonary blood flow; increased pulmonary pressures.
- Atrial Septal Defect (ASD)
- Ventricular Septal Defect (VSD)
- Patent Ductus Arteriosus (PDA)
What is the shunt volume is dependent upon three factors:
Left to right shunt lesion
(1) size of defect
(2) pressure gradient between chambers or vessels
(3) peripheral outflow resistance
What happens to untreated left to right shunt lesion?
untreated shunts can result in pulmonary vascular disease, left ventricular dilatation and dysfunction, right ventricular hypertension and hypertrophy (RVH), and ultimately R to L
Shunts
ASD =
Atrial Septal Defect
3 types of atrial septal defect:
- ostium primum (common in Down syndrome)
- ostium secundum (most common type, 50-70%)
- sinus venosus (defect located at entry of superior vena cava into right atrium)
Ostium primum:
ASD
common in Down syndrome
Ostium secundum:
ASD
most common type, 50-70%
Sinus venosus:
ASD
defect located at entry of superior vena cava into right atrium
ASD - epidemiology:
6-8% of congenital heart lesions
ASD - Natural history:
- 80-100% spontaneous closure rate if ASD diameter <8 mm if remains patent
- congestive heart failure (CHF) and pulmonary hypertension can develop in adult life
ASD - linical presentation:
- History: often asymptomatic in childhood
- Physical exam: grade 2 3/6 pulmonic outflow murmur, widely split and fixed S2
ASD - Investigation:
- ECG: right axis deviation (RAD), mild RVH, right bundle branch block (RBBB)
- CXR: increased pulmonary vasculature
ASD - Management:
elective surgical or catheter closure between 2-5 yr of age
VSD =
Ventricular Septal Defect
What is the frequency of ventricular septal defect?
most common congenital heart defect (30-50%)
- small VSD (majority)
Small VSD - History:
history: asymptomatic, normal growth, and development
Small VSD: Physical exam:
early systolic to holosystolic murmur, best heard at LLSB, thrill
Small VSD - Investigation:
ECG and CXR are normal
Small VSD - management:
most close spontaneously
moderate-to-large VSD - Epidemiology:
CHF by 2 mo; late secondary pulmonary hypertension if left untreated
moderate-to-large VSD - History:
delayed growth, decreased exercise tolerance, recurrent URTIs or “asthma” episodes
moderate-to-large VSD - Physical exam:
holosystolic murmur at LLSB, mid-diastolic rumble at apex, size of VSD is inversely related to intensity of murmur
moderate-to-large VSD - Investigations:
- ECG: left ventricular hypertrophy (LVH), left atrial hypertrophy (LAH), RVH
- CXR: increased pulmonary vasculature, cardiomegaly, CHF
moderate-to-large VSD - Management:
treatment of CHF and surgical closure by 1 yr old
moderate-to-large VSD - Management:
treatment of CHF and surgical closure by 1 yr old
PDA=
Patent Ductus Arteriosus
Patent Ductus Arteriosus
patent vessel between descending aorta and left pulmonary artery (normally, functional closure within first 15 h of life, anatomical closure within first days of life)
PDA - Epidemiology:
5-10% of all congenital heart defects delayed closure of ductus is common in premature infants (1/3 of infants <1750g); this is different from PDA in term infants
PDA - Natural history:
spontaneous closure common in premature infants, less common in term infants
PDA - History:
asymptomatic, or have apneic or bradycardic spells, poor feeding, accessory muscle use, CHF
PDA - Physical exam:
- tachycardia
- bounding pulses
- hyperactive precordium
- wide pulse pressure
- continuous “machinery” murmur best heard at left infraclavicular area
PDA - Investigations:
- ECG: may show LAE, LVH, RVH
- CXR: normal to mildly enlarged heart, increased pulmonary vasculature, prominent pulmonary artery
- ECHO: diagnostic
PDA - Management:
- indomethacin (Indocid®): PGE2 antagonist (PGE2 maintains ductus arteriosus patency) is only effective in premature infants - catheter or surgical closure if PDA causes respiratory compromise, FTT, or persists beyond 3 months of life.
PDA - Obstructive lesions:
present with decreased urine output, pallor, cool extremities and poor pulses, shock or sudden collapse
- Coarctation of the Aorta
- Aortic Stenosis
- Pulmonary Stenosis
Coarctation of the Aorta:
narrowing of aorta (almost always at the level of the ductus arteriosus)
Coarctation of the Aorta - Epidemiology:
commonly associated with bicuspid aortic valve (50%); Turner syndrome (35%)
Coarctation of the Aorta - History:
often asymptomatic
Coarctation of the Aorta - Physical exam:
- upper extremity systolic pressures of 140-145 mmHg
- few have high BP in infancy (160-200 mmHg systolic), but this decreases as collaterals develop
- decreased blood pressure and weak/absent pulses in lower extremities radial-femoral delay
- absent or systolic murmur with late peak at apex, left axilla, and left back
- if severe, presents with shock in the neonatal period when the ductus closes
Coarctation of the Aorta - Investigations:
ECG shows RVH early in infancy, LVH later in childhood
Coarctation of the Aorta - Prognosis:
- can be complicated by hypertension; if associated with other lesions (e.g. PDA, VSD)
- can lead to CHF
Coarctation of the Aorta - Management:
- give prostaglandins to keep ductus arteriosus patent for stabilization and perform surgical correction in neonates.
- For older infants and children balloon arterioplasty may be an alternative to surgical correction.
Aortic Stenosis - 4 Types:
- valvular (75%)
- subvalvular (20%)
- supravalvular and idiopathic hypertrophic subaortic stenosis (IHSS) (5%)
Aortic Stenosis - History:
- often asymptomatic
- but may be associated with CHF, exertional chest pain, syncope or sudden death
Aortic Stenosis - Physical exam:
systolic ejection murmur (SEM) at RUSB with aortic ejection click at the apex (only for valvar stenosis)
Aortic Stenosis - Management:
valvular stenosis is usually treated with balloon valvuloplasty patients with subvalular or supravalvular stenosis require surgical repair, exercise restriction required
Pulmonary Stenosis - 3 Types:
- Valvular (90%)
- Subvalvular
- Supravalvular
Pulmonary Stenosis - Definition of critical pulmonic stenosis:
inadequate pulmonary blood flow, dependent on ductus for oxygenation, progressive hypoxia and cyanosis
Pulmonary Stenosis - natural history:
may be part of other congenital heart lesions (e.g. Tetralogy of Fallot) or in association with syndromes (e.g. congenital rubella, Noonan syndrome)
Pulmonary Stenosis - History:
spectrum from asymptomatic to CHF
Pulmonary Stenosis - Physical examination:
- wide split S2 on expiration
- SEM at LUSB
- pulmonary ejection click (for valvular lesions)
Pulmonary Stenosis - Investigation:
- ECG: RVH
- CXR: post-stenotic dilation of the main pulmonary artery
Pulmonary Stenosis - Management:
surgical repair if critically ill, or if symptomatic in older infants/children
Right to left shunt lesions:
- Tetralogy of Fallot
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