Updated: Jun 12, 2009
In simple terms, an atrial septal defect (ASD) is a deficiency of the atrial septum. Atrial septal defects account for about 10-15% of all congenital cardiac anomalies and are the most common congenital cardiac lesion presenting in adults.1 Sinus venosus atrial septal defects account for only 10% of atrial septal defects. The remaining atrial septal defects are ostium secundum type (70%), ostium primum type (20%), and unroofed coronary sinus, or coronary sinus septal defects, (<1%). Most children with sinus venosus atrial septal defects are asymptomatic but may develop symptoms as they age.
Excellent surgical results with a mortality rate near 0% can be expected. This is particularly true in patients who undergo repair when younger than 15 years. An atrial septal defect was the first lesion repaired using cardiopulmonary bypass in 1954 by John Gibbon, MD, at the Mayo Clinic.
The more common sinus venosus type defect (often referred to as the "usual type") occurs in the upper atrial septum and is contiguous with the superior vena cava (SVC). The lesion is rostral and posterior to the fossa ovalis (where secundum type defects occur) and is separate from it. It is almost always associated with anomalous pulmonary venous drainage of the right upper pulmonary vein into the SVC.
Sinus venosus defects represent approximately 1% of congenital cardiac lesions.
Surgical repair in the first 2 decades of life is associated with a mortality rate near zero. Life expectancy approaches that of the general population if the defect is repaired during this time. Cardiac size rapidly regresses after surgery, and the functional result is excellent. In cases of repair during adulthood, life expectancy may be decreased despite successful repair. Surgical morbidity rates are related to early postoperative pericardial effusion, early postoperative pulmonary venous or systemic venous obstruction, and supraventricular arrhythmias. If the baffle directing pulmonary venous blood to the left atrium is not placed correctly, it may obstruct pulmonary venous drainage. If the baffle bulges into the SVC, it may obstruct SVC inflow, necessitating the placement of an augmentation patch on the anterior surface of the SVC and right atrial junction.
Untreated atrial septal defects are associated with a significantly shortened life expectancy. After age 20 years, the mortality rate is approximately 5% per decade with 90% of patients dead by age 60 years. These patients present with an increase in left-to-right shunting and occasionally with congestive heart failure with pulmonary hypertension in the fourth to sixth decades of life. Guidelines for the diagnosis and treatment of pulmonary artery hypertension have been established.2 Late problems in untreated patients also include the risk of paradoxical embolus as well as atrial fibrillation, pulmonary hypertension, and right heart failure.
No racial predilection is known.
Atrial septal defects affect females more often than males. Female-to-male ratio is 2:1. No difference in outcome is associated with sex.
Sinus venosus atrial septal defects are congenital lesions present at birth. The age at presentation depends on the size of the left-to-right shunt. Atrial septal defects in infancy are usually asymptomatic. They are usually detected by echocardiography while undergoing a cardiac evaluation.
Sinus venosus atrial septal defects, like most atrial septal defects, are diagnosed upon detection of a murmur, a split second heart sound, and/or right heart enlargement on EKG in the usually asymptomatic patient.
| Atrial Septal Defect, Coronary Sinus | Partial Anomalous Pulmonary Venous
Connection |
| Atrial Septal Defect, Ostium Primum | Pulmonary Stenosis, Valvar |
| Atrial Septal Defect, Ostium Secundum | |
| Atrioventricular Septal Defect, Partial and
Intermediate | |
| Cor Triatriatum |
Cardiac catheterization is usually not required in the preoperative assessment of patients with sinus venosus atrial septal defect, but it may be considered in the following circumstances:
Surgical correction is the mainstay of therapy.
Medical management is ineffective in the treatment of sinus venosus defects. The rare patient who presents in congestive heart failure can be stabilized medically with diuretics and inotropic support.
These agents provide myocardial support in patients with dysfunction secondary to pulmonary overcirculation from left-to-right shunting. Positive inotropic agents increase the force of contraction of the myocardium and are used to treat acute and chronic congestive heart failure (CHF). Some may also increase or decrease the heart rate (ie, positive or negative chronotropic agents), provide vasodilatation, or improve myocardial relaxation. These additional properties influence the choice of drug for specific circumstances.
Exerts its inotropic effects by increasing amount of intracellular calcium available during excitation-contraction coupling. One of numerous inotropic agents that can be used in infants with congenital cardiac defects. Generally used for long-term administration and is rarely drug of choice for acute management of heart failure in ICU setting.
Total digitalizing dose (TDD):
0.75-1.5 mg PO divided tid; 0.5-1 mg IV/IM divided tid
Divide TDD as follows: 50% initially; 25% 6-12 h later; 25% and the final 6-12 h later (one half, one quarter, one quarter)
Maintenance dose:
0.125-0.5 mg/d PO; 0.1-0.4 mg/d IV/IM
TDD:
Preterm neonate: 20-30 mcg/kg/d PO; 15-25 mcg/kg/d IV/IM
Term neonate: 25-35 mcg/kg/d PO; 20-30 mcg/kg IV/IM
1 month to 2 years: 35-60 mcg/kg/d PO; 30-50 mcg/kg/d IV/IM
2-5 years: 30-40 mcg/kg/d PO; 25-35 mcg/kg/d IV/IM
5-10 years: 20-35 mcg/kg/d PO; 15-30 mcg/kg/d IV/IM
>10 years: 10-15 mcg/kg/d PO; 8-12 mcg/kg/d IV/IM
Divide TDD as follows: 50% initially, 25% 6-12 h later; and the final 25% 6-12 h later (one half, one quarter, one quarter)
Maintenance dose:
Preterm neonate: 5-7.5 mcg/kg/d PO divided bid; 4-6 mcg/kg/d IV/IM divided bid
Term neonate: 6-10 mcg/kg/d PO divided bid; 5-8 mcg/kg/d IV/IM divided bid
1 month to 2 years: 10-15 mcg/kg/d PO divided bid; 7.5-12 mcg/kg/d IV/IM divided bid
2-5 years: 7.5-10 mcg/kg/d PO divided bid; 6-9 mcg/kg/d IV/IM divided bid
5-10 years: 5-10 mcg/kg/d PO divided bid; 4-8 mcg/kg/d IV/IM divided bid
>10 years: 2.5-5 mcg/kg/d PO; 2-3 mcg/kg/d IV/IM qd
Medications that may increase digoxin levels include alprazolam, benzodiazepines, bepridil, captopril, cyclosporine, propafenone, propantheline, quinidine, diltiazem, aminoglycosides, PO amiodarone, anticholinergics, diphenoxylate, erythromycin, felodipine, flecainide, hydroxychloroquine, itraconazole, nifedipine, omeprazole, quinine, ibuprofen, indomethacin, esmolol, tetracycline, tolbutamide, and verapamil
Medications that may decrease serum digoxin levels include aminoglutethimide, antihistamines, cholestyramine, neomycin, penicillamine, aminoglycosides, PO colestipol, hydantoins, hypoglycemic agents, antineoplastic treatment combinations (including carmustine, bleomycin, methotrexate, cytarabine, doxorubicin, cyclophosphamide, vincristine, procarbazine), aluminum or magnesium antacids, rifampin, sucralfate, sulfasalazine, barbiturates, kaolin/pectin, and aminosalicylic acid
Documented hypersensitivity; digitalis-induced toxicity, AV block, idiopathic subaortic stenosis, constrictive pericarditis
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Hypokalemia may reduce positive inotropic effect of digitalis; IV calcium may produce arrhythmias in digitalized patients; hypercalcemia predisposes patient to digitalis toxicity, and hypocalcemia can make digoxin ineffective until serum calcium levels are normal; magnesium replacement therapy must be instituted in patients with hypomagnesemia to prevent digitalis toxicity; patients diagnosed with incomplete AV block may progress to complete block when treated with digoxin; exercise caution in hypothyroidism, hypoxia, and acute myocarditis
Adrenergic agonists often are used for inotropic support in critical care setting for their rapid onset of action and rapid time to peak effect, which make them easier to titrate to effect
1-20 mcg/kg/min continuous IV infusion; not to exceed 50 mcg/kg/min
Neonates: 1-20 mcg/kg/min continuous IV infusion
Infants and children: Administer as in adults
Phenytoin, alpha-adrenergic and beta-adrenergic blockers, general anesthesia, and MAOIs increase and prolong effects of dopamine
Documented hypersensitivity; pheochromocytoma or ventricular fibrillation
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Treat hypovolemia before infusion; administration through a central vein is recommended; do not use umbilical artery for infusion; if dosages >20 mcg/kg/min are required, consider a different agent (eg, epinephrine, dobutamine)
These agents are used for management of right heart failure and pulmonary edema. They promote excretion of water and electrolytes by the kidneys.
Highly effective first-line diuretic in newborns and infants. A sulfonamide derivative, it exerts its effects on the loop of Henle and distal renal tubule, inhibiting reabsorption of sodium and chloride.
10-200 mg PO/IV initially; titrate dose to effect; not to exceed 600 mg/d
Continuous IV infusions may be more successful; not to exceed 0.4 mg/kg/h
1-2 mg/kg/dose PO/IV bid/qid; titrate dose to effect; not to exceed 6 mg/kg/dose bid/qid
Metformin decreases furosemide concentrations; furosemide interferes with hypoglycemic effect of antidiabetic agents and antagonizes muscle relaxing effect of tubocurarine; auditory toxicity appears to be increased with coadministration of aminoglycosides and furosemide, hearing loss of varying degrees may occur; anticoagulant activity of warfarin may be enhanced when taken concurrently with this medication; increased plasma lithium levels and toxicity are possible when taken concurrently with this medication
Documented hypersensitivity; hepatic coma, anuria, and state of severe electrolyte depletion
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Monitor serum potassium levels closely; may produce intravascular dehydration, severe hypokalemia, and significant hypochloremic metabolic acidosis; inform patients of potential for photosensitivity; may produce hyperuricemia; may produce deafness caused by ototoxicity; most popular strengths of digoxin and furosemide are white tablets of approximately equal size and may be confused by patients; administer oral dose with food or milk to decrease stomach upset
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Mas MS, Bricker JT. Clinical Physiology of Left-to-Right Shunts. In: Garson A, Bricker JT, McNamara DG, eds. The Science and Practice of Pediatric Cardiology. Vol 2. Lippincott Williams & Wilkins; 1990:999-1001.
Murphy JG, Gersh BJ, McGoon MD, et al. Long-term outcome after surgical repair of isolated atrial septal defect. Follow-up at 27 to 32 years. N Engl J Med. Dec 13 1990;323(24):1645-50. [Medline].
Radzik D, Davignon A, van Doesburg N, et al. Predictive factors for spontaneous closure of atrial septal defects diagnosed in the first 3 months of life. J Am Coll Cardiol. Sep 1993;22(3):851-3. [Medline].
Sachweh JS, Daebritz SH, Hermanns B, et al. Hypertensive pulmonary vascular disease in adults with secundum or sinus venosus atrial septal defect. Ann Thorac Surg. Jan 2006;81(1):207-13. [Medline].
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sinus venosus, atrial septal defect, ASD, superior vena cava type subcaval ASD, SVASD, atrial septum, congenital heart defect, congenital cardiac anomaly, congestive heart failure, murmur, treatment, diagnosis, heart problems, heart disease, heart anomaly
Gary M Satou, MD, FASE, Director, Pediatric Echocardiography, Mattel Children's Hospital at University of California at Los Angeles; Associate Clinical Professor, Department of Pediatrics, David Geffen School of Medicine at University of California at Los Angeles
Gary M Satou, MD, FASE is a member of the following medical societies: American Academy of Pediatrics, American College of Cardiology, American Heart Association, American Society of Echocardiography, and Society of Pediatric Echocardiography
Disclosure: Nothing to disclose.
Brian L Reemtsen, MD, Assistant Professor of Cardiothoracic Surgery, Keck School of Medicine, University of Southern California
Brian L Reemtsen, MD is a member of the following medical societies: American Medical Association, Society of Thoracic Surgeons, and Western Thoracic Surgical Association
Disclosure: Nothing to disclose.
Charles I Berul, MD, Associate Professor of Pediatrics, Harvard Medical School; Senior Associate, Department of Cardiology, Children's Hospital of Boston
Charles I Berul, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Cardiology, American Heart Association, and Society for Pediatric Research
Disclosure: Nothing to disclose.
Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner
Alvin J Chin, MD, Professor of Pediatrics, Division of Cardiology, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine
Alvin J Chin, MD is a member of the following medical societies: American Association for the Advancement of Science and American Heart Association
Disclosure: Nothing to disclose.
Gilbert Z Herzberg, MD, Assistant Professor, Department of Pediatrics, Section of Pediatric Cardiology, New York Medical College; Consulting Staff, Department of Pediatrics, Sound Shore Medical Center
Gilbert Z Herzberg, MD is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.
Stuart Berger, MD, Professor of Pediatrics, Division of Cardiology, Medical College of Wisconsin; Chief of Pediatric Cardiology, Medical Director of Pediatric Heart Transplant Program, Medical Director of The Heart Center, Children's Hospital of Wisconsin
Stuart Berger, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Cardiology, American College of Chest Physicians, American Heart Association, and Society for Cardiac Angiography and Interventions
Disclosure: Nothing to disclose.
The authors and editors of eMedicine gratefully acknowledge the contributions of previous authors Jeff L Myers, MD, PhD, and James Jaggers, MD, to the writing and development of this article.
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