Cyanotic VS. Acyanotic CHD
Acyanotic heart disease |
Cyanotic heart disease |
L to R shunt |
R to L shunt |
obstruction occurring
beyond lungs |
blood passes through pulmonic circulation |
blood bypasses the lungs |
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oxygenation takes place |
no oxygenation occurs |
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levels of deoxygenated blood in systemic circulation |
levels of deoxygenated blood enters systemic circulation |
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no cyanosis |
cyanosis |
Cyanosis: blue mucous membranes, nail beds, & skin secondary to an absolute conc. of deoxygenated Hb of at least 30 g/dL
Description
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ACYANOTIC |
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L to R shunt lesions - extra blood displaced through communication frm L to R side of heart pulm. blood flow pulm. pressures
- shunt vol. dependent upon 3 factors:
1) size of defect
2) pressure gradient b/w chambers / vessels, and
3) peripheral outflow resistance
- untreated shunts can result in pulm. vascular disease, L ventricular dilatation & dysfunction, R ventricular HTN & RVH, and ultimately R to L shunts
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Obstructive lesions - present w/ urine output, pallor, cool extremities & poor pulses, shock, or sudden collapse
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CYANOTIC - syst. venous return re-enters syst. circulation directly
- most prominent feature = cyanosis (O2 sat. <75%)
- hyperoxic test differentiates b/w cardiac & other causes of cyanosis
--> obtain preductal, R radial ABG in room air, then repeat after child inspires 100% O2
--> if PaO2 improves to >150 mmHg, cyanosis less likely cardiac in origin
- pre-ductal & post-ductal pulse oximetry
--> >5% diff. suggests R to L shunt
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1. Acyanotic incl.:
- ASD, VSD, PDA
- Coarctation of aorta, Aortic stenosis, Pulm. stenosis
2. Cyanotic incl.:
- Tetralogy of Fallot
- TGA, Total Anomalous Pulm. Venous Return, Truncus Arteriosus, Hypoplastic L Heart Syndrome
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Atrial Septal Defect
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3 types:` |
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- ostium primum -- common in DS
-- defect located @ mitral / tricuspid valve
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- ostium secundum -- most common type
-- 50-70%
-- defect located @ septum b/w L & R atria
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- sinus venosus -- defect located @ entry of SVC into R atrium
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Epidemiology - 6-8% of congenital heart lesions
- common in pts. w/ certain congenital disorders (eg. DS, FAS)
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Natural history - 80-100% spontaneous closure rate if ASD diameter <8mm
- if remains patent, CHF & pulm. HTN can develop in adult life
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Clinical features - hist.: often asymp. in childhood
- phy. exam: grade 2-3/6 pulm. outflow murmur, widely split, & fixed S2
- children w/ large ASDs may hv. signs of heart failure
--> tachypnea, FTT, hepatomegaly, pulmo. rales/retractions
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Investigations - ECG: RAD, mild RVH, RBBB (normal ECG doesn't rule out)
- CXR: pulmo. vasculature, cardiac enlargement (normal ECG doesn't rule out)
- echo: diagnostic
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Management - elective surgical / catheter closure b/w 2-5 yr, though majority req. no surgery
- size <8 mm will likely spontaneously close
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Ventricular Septal Defect
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most common congenital heart defect (30-50%)
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SMALL VSD (majority) |
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Clinical Features - hist.: asymp., normal growth, & development
- phy. exam: early systolic to holosystolic murmur, best heard at LLSB, thrill
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Investigations - echo to confirm diagnosis
(ECG & CXR are normal)
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Management - most spontaneously close
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MODERATE-TO-LARGE VSD |
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Epidemiology - CHF by 2 mo
- late secondary pulm. HTN if left untreated
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Clinical features - hist.: delayed growth, exercise tolerance, recurrent URTIs or "asthma" episodes
- phy. exam: holosystolic murmur at LLSB,
mid-diastolic rumble @ apex,
size of VSD inversely related to intensity of murmur,
loss of splitting of 2nd heart sound & loud P2 suggests pulm. HTN
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Investigations - ECG: LVH, LAH, RVH (normal ECG doesn't rule it out)
- CXR: pulm. vasculature, cardiomegaly, CHF (normal CXR doesn't rule out)
echo: diagnostic
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Management - tx. of CHF & surgical closure by 1 yr, if surgery req.
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* Size of VSD inversely related to sound of murmur
--> loud murmur = smaller hole
Patent Ductus Arteriosus
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Patent vessel b/.w descending aorta & L pulm. artery - normally, func. closure w/i first 15 hr of life
- anatomical closure w/i first days of life
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Epidemiology - 5-10 % of all CHD
- delayed closure of ductus common in premature infants (1/3 of infants <1750 g)
--> this is diff. frm PDA in term infants
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Natural history - spontaneous closure common in premature infants
- less common in term infants
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Clinical features - hist.: aymp. , or have apneic / bradycardic spells, poor feeding, accessory muscle use, CHF
- phy. exam: tachycardia / gallop rhythm,
bounding pulses,
hyperactive precordium,
wide pulse pressure,
cont. "machinery" murmur best heard @ L infraclavicular area
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Investigations - ECG: may show L atrial enlargement, LVH, RVH
- echo = diagnostic
- CXR: may show normal to mildly enlarged heart, pulm. vasculature, prominent pulm. artery
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Management - indomethacin (Indocid): antagonizes prostaglandin E2, which maintains ductus arteriosus patency
--> only effective in premature infants
- catheter or surgical closure if PDA causes resp. compromise, FTT, or persists beyond 3rd mo of life
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Coarctation of aorta
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Narrowing of aorta - almost always at lvl. of ductus arteriosus
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Epidemiology - commonly ass. w/ bicuspid aortic valve (50%) ; Turner synd. (35%)
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Clinical features - hist.: often asymp.
- phy. exam:
-- BP discrepancy b/w upper & lower extremities ( sus. / severity if > 20 mmHg diff.)
-- diminished / delayed femoral pulses relative to brachial pulses (i.e. brachial-femoral delay)
-- possible systolic murmur w/ late peak @ apex, L axilla, & L back
-- if severe, presents w/ shock in neonatal period when ductus arteriosus closes
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Investigations - ECG shows RVH early in infancy, LVH later in childhood
- echo / MRI for diagnosis
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Prognosis - can be complicated by HTN
- if ass. w/ other lesions (e.g. PDA, VSD) can lead to CHF
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Management - give prostaglandins to keep ductus arteriosus patent for stabilization & perform surgical correction in neonates
- for older infants & children balloon arterioplasty may be an alternative to surgical correction
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Aortic Stenosis
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4 types` - valvular (75%)
- subvalvular (20%)
- supravalvular, & idiopathic hypertrophic subaortic stenosis (5%)
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Clinical features - hist.: often asymp. , b/ may be ass. w/ CHF, exertional chest pain, syncope, or sudden death
- phy. exam: SEM @ RUSB w/ aortic ejection click @ apex (only for valvular stenosis)
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Investigations - echo for diagnosis
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Management - valvular stenosis usually treated w/ balloon valvuloplasty, pts. w/ subvalvular or supravalvular stenosis require surgical repair, exercise restriction req.
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Pulmonary Stenosis
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3 types - valvular (90%)
- subvalvular
- or supravalvular
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Definition of critical Pulm. S. Inadequate pulm. blood flow,
Dependent on ductus arteriosus for oxygenation,
Progressive hypoxia & cyanosis
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Natural history - may be part of other congenital heart lesions (e.g. Tetralogy of Fallot)
- or in ass. w/ syndromes (e.g. congenital rubella, Noonan synd.)
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Clinical features - hist.: spectrum frm asymp. to CHF
- phy. exam: wide split S2 on expiration,
SEM @ LUSB,
pulmonary ejection click (for valvular lesions)
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Investigations - ECG findings: RVH
- CXR: post-stenotic dilation of main pulm. artery (due to velocity jest past stenotic valve)
- echo: diagnostic
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Management - surgical repair if critically ill or if symp. in older infants/children
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Tetralogy of Fallot
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Epidemiology - 10% of all CHD
- most common cyanotic heart defect diagnosed beyond infancy w/ peak incidence @ 2-4 mo
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Pathophysiology - embryological defect due to ant. & superior deviation of outlet septum leading to: VSD, RVOTO (i.e. pulm. stenosis / subpulm. valve stenosis), overriding aorta, & RVH
--> infants may initially hv. a L R shunt (∴ no cyanosis)
--> however, RVOTO = progressive, leading to R L shunting w/ hypoxemia & cyanosis
--> degree of RVOTO determines direction & degree of shunt, & ∴, extent of clinical cyanosis & degree of RVH
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Clinical features - hist.: hypoxic "tet" spells
--> during exertional states (crying, exercise), increasing pulm. vascular resistance & decrease in sys. resistance causes in R-to-L shunting
--> clinical features incl.
paroxysms of rapid & deep breathing, irritability & crying,
cyanosis,
intensity of murmur { flow across RVOTO),
pt. squatting for relief ( peripheral resistance, R to L shunting)
--> if severe, can lead to lvl. of consciousness, seizures, death
phy. exam:
--> single loud S2 due to severe pulm. stenosis (i.e. RVOTO)
--> SEM @ LLSB
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Investigations - ECG: RAD, RVH
- CXR: boot-shaped heart, pulm. vasculature, R aortic arch (in 25%)
- echo: diagnostic
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Management of spells O2, knee-chest position, fluid bolus, morphine sulfate, propranolol, phenylephrine
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Treatment - surgical repair @ 4-6 mo of age
- earlier if marked cyanosis or "tet" spells
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Transposition of the Great Arteries
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Epidemiology - 3-5 % of all congenital cardiac lesions
- most common cyanotic CHD in neonates
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Pathophysiology parallel pulm. & syst. circulations
- Systemic: body RA RV aorta body
- Pulmonary: lungs LA LV pulm. artery lungs
- survival dependent on mixing through PDA, ASD, or VSD
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Physical exam - neonates: ductus arteriosus closure causes rapidly progressive severe hypoxemia unresponsive to O2 therapy, acidosis, & death
- VSD present: cyanosis not prominent ; CHF w/i first wks of life
- VSD absent: no murmur
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Investigations - ECG: RAD, RVH, or may be normal
- CXR: egg-shaped heart w/ narrow mediastinum ("egg on a string")
- echo: diagnostic
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Management - symptomatic neonates: prostaglandin E1 infusion to keep ductus open until balloon atrial septostomy
- surgical repair: arterial switch performed in first 2 wk in those w/o VSD while LV muscle still strong
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Total Anomalous Pulmonary Venous Return
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Epidemiology 1-2% of CHD
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Pathophysiology - all pulm. veins drain into R-sided circulation (syst. veins, RA)
- no direct oxygenated pulm. venous return to L atrium
- often ass. w/ obstruction @ connection sites
- ASD must be present for oxygenated blood to shunt into LA & syst. circulation
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Management surgical repair in all cases & req. urgently for severe cyanosis
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Truncus Arteriosus
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Pathophysiology - single great vessel gives rise to aorta, pulm. & coronary arteries
- truncal valve overlies a large VSD
- potential for coronary ischemia w/ fall in pulm. vascular resistance
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Management surgical repair w/i first 6 wk of life
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Hypopplastic Left Heart Syndrome
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Epidemiology - 1-3% of CHD
- most common cause of death frm CHD in first mo of life
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Pathophysiology - LV hypoplasia may incl.
--> atretic / stenotic mitral and/or aortic valve
--> small ascending aorta
--> coarctation of aorta w/ resultant syst. hypoperfusion
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Systemic circulation dependent on ductus patency Upon closure of ductus, infant presents w/ circulatory shock & metabolic acidosis
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Management - intubate & correct metabolic acidosis
- IV infusion of prostaglandin E1 to keep ductus open
- surgical palliation (overall survival 50% to late childhood) or heart transplant
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