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Ostium Primum Atrial Septal Defects Clinical Presentation

  • Author: Shannon M Rivenes, MD; Chief Editor: P Syamasundar Rao, MD  more...
Updated: Aug 04, 2015


Children with smaller ostium primum atrial septal defects (ASDs) and little or no mitral regurgitation or left ventricle to right atrium shunting are usually asymptomatic. Those with significant pulmonary overcirculation and/or significant mitral regurgitation tend to present in infancy with congestive heart failure (CHF). Tachypnea and tachycardia are noted at rest and are exacerbated with crying or exertion. Feeding is accompanied by dyspnea, diaphoresis, and an increased work of breathing. The combination of feeding difficulties and increased metabolic demands results in failure to thrive, which may be severe and/or intractable.



Characteristic features of trisomy 21 may be detected, such as hypotonia and hyperflexibility. These include the following:

  • Short, flat nose with a flat nasal bridge
  • Oblique palpebral fissures
  • Abundant neck skin
  • Large and protuberant tongue
  • Short, broad hands with a shorter fifth finger (clinodactyly)
  • Simian crease
  • Inner epicanthal fold extending onto the lower lid
  • Brushfield spots (speckled iris)

Infants and children with partial atrioventricular (AV) septal defects and significant mitral regurgitation have poor development and are tachypneic and tachycardic at rest. A hyperinflated thorax, bulging precordium, and Harrison grooves are often present. Most children, however, have a milder degree of mitral regurgitation and, in general, appear normally developed and thriving on examination.

The cardiac examination in isolated ostium primum ASDs or partial AV canal defects with minimal mitral regurgitation is similar to that in other forms of ASDs. Patients typically have an increased right ventricular impulse secondary to volume overload. The first heart sound is normal. The second heart sound is fixed or at least widely split. A systolic ejection murmur is heard loudest at the upper left sternal border, with radiation to both lung fields. A click is not present. A tricuspid mid-diastolic rumble is present in children with larger shunts (pulmonary-to-systemic flow ratio > 2:1) and is appreciated at the lower left sternal border.

The murmur of mitral insufficiency is typically high-pitched, holosystolic, and loudest at the apex. The murmur usually radiates to the axilla but may radiate preferentially to the sternal edge secondary to streaming of the regurgitant flow across the atrial septum.

If pulmonary hypertension is present, significant changes are noted in the physical examination. The pulmonary component of the second heart sound becomes loud. The splitting of the second heart sound narrows and eventually may become single. The diastolic tricuspid rumble disappears. A holosystolic murmur of tricuspid regurgitation becomes noticeable as the right ventricle dilates. This murmur is usually loudest at the lower left sternal border and becomes higher pitched as the right ventricular pressure increases. A short midsystolic murmur may be present secondary to flow into a dilated pulmonary artery. A Graham-Steell pulmonary insufficiency murmur may be appreciated as an early diastolic decrescendo murmur at the mid left sternal border.

Contributor Information and Disclosures

Shannon M Rivenes, MD Assistant Professor, Department of Pediatrics, Division of Pediatric Cardiology, Texas Children’s Hospital and Baylor College of Medicine

Shannon M Rivenes, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American College of Cardiology, American Heart Association, American Society of Echocardiography

Disclosure: Nothing to disclose.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Alvin J Chin, MD Emeritus Professor of Pediatrics, 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, Society for Developmental Biology, American Heart Association

Disclosure: Nothing to disclose.

Chief Editor

P Syamasundar Rao, MD Professor of Pediatrics and Medicine, Division of Cardiology, Emeritus Chief of Pediatric Cardiology, University of Texas Medical School at Houston and Children's Memorial Hermann Hospital

P Syamasundar Rao, MD is a member of the following medical societies: American Academy of Pediatrics, American Pediatric Society, American College of Cardiology, American Heart Association, Society for Cardiovascular Angiography and Interventions, Society for Pediatric Research

Disclosure: Nothing to disclose.

Additional Contributors

Paul M Seib, MD Associate Professor of Pediatrics, University of Arkansas for Medical Sciences; Medical Director, Cardiac Catheterization Laboratory, Co-Medical Director, Cardiovascular Intensive Care Unit, Arkansas Children's Hospital

Paul M Seib, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Cardiology, American Heart Association, Arkansas Medical Society, International Society for Heart and Lung Transplantation, Society for Cardiovascular Angiography and Interventions

Disclosure: Nothing to disclose.

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ECG from a patient with a partial atrioventricular septal defect. The PR interval is mildly prolonged. Left axis deviation with Q waves in leads I and aVL are present, consistent with a counterclockwise loop in the frontal plane. Right atrial enlargement and an rsR' pattern in the right chest leads also are noted.
Two-dimensional, apical, 4-chamber echocardiogram of a partial atrioventricular (AV) canal defect. The asterisk (*) delineates an area of dropout in the inferior atrial septum at the site of the primum atrial septal defect. The AV valves are separate but aligned at the same horizontal level, consistent with a 2-orifice common AV valve. In systole, the medial leaflets of the right- and left-sided AV valves demonstrate attachments to the crest of the interventricular septum, allowing no ventricular level shunting. RA = Right atrium; LA = Left atrium; RV = Right ventricle; LV = Left ventricle.
Gross pathology specimen viewed from the opened left atrium and left ventricle, demonstrating a partial atrioventricular (AV) canal defect. An ostium primum atrial septal defect (ASD) marked by an asterisk (*) is visualized in the inferior aspect of the interatrial septum. An ostium secundum ASD marked by 2 asterisks (**) is also noted. The mitral valve is cleft and the leaflets are thickened and rolled, suggestive of chronic mitral regurgitation. LA = Left atrium; LV = Left ventricle; MV = Mitral valve.
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