Snapshot
A 15-year-old boy presents to his pediatrician’s office for exercise intolerance. He says he is unable to keep up with his friends during physical activities such as sports, which is new to him. On physical exam, a loud S1 and a fixed split S2 is appreciated during cardiac auscultation. He is sent for a chest radiograph, electrocardiogram, and echocardiogram for further evaluation.
Introduction
- Clinical definition
- a congenital defect resulting in an opening in the interatrial septum of the heart
- Epidemiology
- demographics
- present at birth
- risk factors
- family history
- exposure to alcohol or cigarette smoking in utero
- demographics
- Etiology
- ostium secundum defect (most common)
- secundum ASD is often an isolated congenital defect
- can result in paradoxical emboli from deep venous thromboses
- ostium primum defect
- primum ASD is often associated with other cardiac defects
- ostium secundum defect (most common)
- Pathogenesis
- atrial septal defect results from missing tissue rather than unfused tissue
- left-to-right shunting in the heart, causing increased pulmonary blood flow and alterations in the pulmonary vasculature
- over time, with severe defects, this eventually results in pulmonary hypertension and Eisenmenger syndrome
- Associated conditions
- fetal alcohol syndrome
- Down syndrome
- Patau syndrome
- Prognosis
- may be asymptomatic or may progress to heart failure
- mortality highest in infants and adults > 65 years of age
Presentation
- Symptoms
- usually asymptomatic in childhood
- patients with large ASDs will develop symptoms later in life
- exercise intolerance
- poor weight gain
- frequent pulmonary infections
- Physical exam
- cardiac auscultation
- loud S1
- wide and fixed splitting in S2
- parasternal heave
- cardiac auscultation
midsystolic pulmonary flow murmur (secondary to increased blood flow across the pulmonic valve) 
Imaging
- Radiography
- indication
- often an initial test to rule out other pathologies
- views
- chest
- findings
- right heart enlargement
- increased vascular markings
- indication
- Echocardiography
- indications
- diagnostic test
- most specific test
- findings
- ASD
- indications
Studies
- Electrocardiogram
- indication
- to assess for any arrhythmias
- findings
- right atrial enlargement
- right bundle branch block
- indication
- Making the diagnosis
- based on clinical presentation and echocardiogram
| Snapshot |
| A 15-year-old boy presents to his pediatrician’s office for exercise intolerance. He says he is unable to keep up with his friends during physical activities such as sports, which is new to him. On physical exam, a loud S1 and a fixed split S2 is appreciated during cardiac auscultation. He is sent for a chest radiograph, electrocardiogram, and echocardiogram for further evaluation. |
| Introduction |
| Clinical definitiona congenital defect resulting in an opening in the interatrial septum of the heartEpidemiologydemographicspresent at birthrisk factorsfamily historyexposure to alcohol or cigarette smoking in uteroEtiologyostium secundum defect (most common)secundum ASD is often an isolated congenital defect can result in paradoxical emboli from deep venous thrombosesostium primum defectprimum ASD is often associated with other cardiac defectsPathogenesis atrial septal defect results from missing tissue rather than unfused tissueleft-to-right shunting in the heart, causing increased pulmonary blood flow and alterations in the pulmonary vasculatureover time, with severe defects, this eventually results in pulmonary hypertension and Eisenmenger syndrome Associated conditionsfetal alcohol syndromeDown syndromePatau syndromePrognosismay be asymptomatic or may progress to heart failuremortality highest in infants and adults > 65 years of age |
| Presentation |
| Symptomsusually asymptomatic in childhoodpatients with large ASDs will develop symptoms later in lifeexercise intolerancepoor weight gainfrequent pulmonary infectionsPhysical examcardiac auscultationloud S1wide and fixed splitting in S2 parasternal heavemidsystolic pulmonary flow murmur (secondary to increased blood flow across the pulmonic valve) |
| Imaging |
| Radiographyindicationoften an initial test to rule out other pathologiesviewschestfindingsright heart enlargementincreased vascular markingsEchocardiographyindicationsdiagnostic testmost specific testfindings ASD |
| Studies |
| Electrocardiogramindicationto assess for any arrhythmiasfindingsright atrial enlargementright bundle branch blockMaking the diagnosisbased on clinical presentation and echocardiogram |
| Differential |
| Ventricular septal defect distinguishing factorhigh-pitched and harsh holosystolic murmurAortic stenosisdistinguishing factorparadoxical splitting of S2 (heard on expiration rather than inspiration)crescendo-decrescendo systolic ejection murmurInnocent/physiologic murmursdistinguishing factormost common murmur of childhoodgrade < 2 intensity, minimal radiation, musical quality, softer intensity when sitting upright |
| Treatment |
| Management approachmild defects can be left untreated6 months after procedures, patients must receive prophylaxis for infective endocarditis after dental proceduresMedicalpalivizumabindicationsinfants with symptomatic ASDpassive immunization against the respiratory syncytial virus (RSV)Operativepercutaneous or catheter device closureindicationsmaller isolated effectsevidence of right heart overloadsecundum ASDcomplicationsarrhythmiasthrombosis from the devicesurgical repairindicationshunt ratio > 1.5:1primum ASDevidence of right heart overload |
| Complications |
| Heart failure Eisenmenger syndrome Paradoxical embolivenous emboli may run through ASD to become systemic arterial emboli |