ATRIAL SEPTAL DEFECT (ASD)

ATRIAL SEPTAL DEFECT (ASD) - Ryan Johnson, MD; Brent J. Barber, MD
BASICS
DESCRIPTION
• A defect or opening in the atrial septum allowing flow of blood between the two chambers
• Shunting
- Typically left to right; occurs in late ventricular systole and early diastole
- Degree depends on size of the defect and relative compliance of the two ventricles
- Can be minimal right-to-left shunting in early ventricular systole, especially during inspiration
• Symptoms typically occur due to right ventricular and pulmonary vascular volume overload, sometimes with resultant pulmonary hypertension
• Types
- Ostium secundum occurs in the region of the fossa ovalis (most common).
- Sinus venosus occurs in the superior-posterior septum, usually associated with partial anomalous pulmonary venous return.
- Ostium primum occurs in the inferior portion of the septum (often associated with cleft mitral valve).
• System(s) Affected: Cardiovascular, Pulmonary
ALERT
Geriatric Considerations
Defects may still be closed surgically.
Pediatric Considerations
Most frequently appears in this age group
Pregnancy Considerations
Evaluate prior to pregnancy, because condition may worsen.
GENERAL PREVENTION
Evaluate prior to pregnancy
EPIDEMIOLOGY
• Predominant age: Newborn, but may be diagnosed at any age
• Predominant sex: Female > Male (2:1)
Incidence
Accounts for 10% of congenital heart defects
RISK FACTORS
• Congenital heart disease
• Family history
Genetics
Congenital, associated with multiple syndromes, rarely familial
ETIOLOGY
Unknown
ASSOCIATED CONDITIONS
• Mitral stenosis
• Mitral regurgitation
• Anomalous pulmonary venous return
• Multiple congenital syndromes


DIAGNOSIS
SIGNS AND SYMPTOMS
• Easy fatigability, dyspnea on exertion, heart failure (late)
• Signs vary according to extent of shunting
- Prominent precordial bulge
- Right ventricular lift
- Palpable pulmonary artery pulse
- Fixed, widely split S2
- Pulmonic flow murmur
- Low-pitched diastolic murmur at left lower sternal border
- Cyanosis and clubbing (with severe pulmonary hypertension: Eisenmenger syndrome)
- Stroke due to paradoxical emboli
ALERT
Pediatric Considerations Childhood symptoms
• Usually minimal
• Can include failure to thrive and frequent pulmonary infections
TESTS
Lab
• ECG findings
- Ostium secundum: Rightward axis, right ventricular hypertrophy, rSR' pattern in V1
- Sinus venosus: Leftward axis, inverted P wave in lead III
- Ostium primum: Leftward axis Note: All may be associated with PR prolongation.
Imaging
• X-ray: Varying degrees of cardiac enlargement, increased pulmonary vascular workings
• Cardiac magnetic resonance imaging
• Cardiac catheterization (indicated in select patients) demonstrates right ventricle enlargement and location of the shunt.
• Echocardiography
Diagnostic Procedures/Surgery
• Cardiac magnetic resonance imaging
• Cardiac angiography
• Echo and Doppler
• Transesophageal echo in adults
Pathological Findings
• Gross defect in atrial septum
• Dilated right atrium, right ventricle
• Enlarged pulmonary artery
DIFFERENTIAL DIAGNOSIS
Other congenital heart disease, right bundle branch block (for widely split S2)
TREATMENT
GENERAL MEASURES
• Appropriate health care: Referral/evaluation by a cardiologist
• Majority of small ASDs will close spontaneously, however, close follow-up is warranted. (1,2) [B]
Activity
As tolerated
MEDICATION (DRUGS)
• Antibiotic prophylaxis (not for secundum atrial septal defect)
• Anticoagulation if paradoxical emboli
SURGERY
• Closure via percutaneous transcatheter device or surgery(particularly when the pulmonary systemic flow ratio is 1.5:1, or evidence of right heart enlargement)
• Percutaneous transcatheter device closure of secundum atrial septal defects and patent foramen ovale is now considered a standard and low-risk procedure that has widely replaced the surgical approach. (3)[A]
• Closure is usually delayed until preschool age (2-4 years), except for large defects to be repaired earlier.
• Closure in adult patients with stroke reduces the risk of further neurologic events. (4)[B] However, device closure of a patent foramen ovale in the adult population remains controversial.
• New evidence suggests symptomatic migraine relief following patent foramen ovale closure. (5)[B]
FOLLOW-UP
PROGNOSIS
• Course: chronic
• 50% mortality by age 50 years in untreated patients with large defects
• Favorable in surgically treated symptomatic patients
COMPLICATIONS
• Congestive heart failure
• Cyanosis
• Late-onset arrhythmias 10-20 years after surgery (5%)
• Stroke
• Pulmonary hypertension
• Eisenmenger syndrome
• Infective endocarditis
PATIENT MONITORING
• Until defect has closed
• Routine echocardiography follow-up
REFERENCES
1. Helgason H, Jonsdottir G. Spontaneous closure of atrial septal defects. Pediatr Cardiol. 1999;20:195-199.
2. McMahon CJ, Feltes TF, Fraley JK, et al. Natural history of growth of secundum atrial septal defects and implications for transcatheter closure. Heart. 2002;87:256-259.
3. Holzer R, Hijazi ZM. Interventional approach to congenital heart disease. Curr Opin Cardiol. 2004;19:84-90.
4. Onorato E, Melzi G, Casilli F, et al. Patent foramen ovale with paradoxical embolism: Mid-term results of transcatheter closure in 256 patients. J Interv Cardiol. 2003;16:43-50.
5. Morandi E, Anzola GP, Angeli S, et al. Transcatheter closure of patent foramen ovale: A new migraine treatment? J Interv Cardiol. 2003;16:39-42.
6. Friedman WF, Perloff JK Congenital heart disease in infancy and childhood. In: Braunwald E, ed. Heart Disease. 4th ed. Philadelphia: WB Saunders; 1992.
7. Hillis DL, Lange RA, Winniford MD, Page RL. Manual of Clinical Problems in Cardiology. New York: Little, Brown; 1995.
MISCELLANEOUS
See also: Aortic Valvular Stenosis; Coarctation of the Aorta; Complete Atrioventricular (AV) Canal; Patent Ductus Arteriosus; Pulmonic Valvular Stenosis; Tetralogy of Fallot; Ventricular Septal Defect (VSD)