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Endocardial Cushion Defects

  • Author: Mary C Mancini, MD, PhD, MMM; Chief Editor: Park W Willis IV, MD  more...
 
Updated: Sep 15, 2014
 

Background

Endocardial cushion defects, more commonly known as atrioventricular (AV) canal or septal defects, include a range of defects characterized by involvement of the atrial septum, the ventricular septum, and one or both of the AV valves.

These defects can be classified by several methods. A distinction generally is made between partial and complete defects. A complete AV septal defect indicates the presence of both atrial and ventricular septal defects with a common AV valve (see image below). A partial defect indicates atrial septal involvement with separate mitral and tricuspid valve orifices.

Anatomy of the endocardial cushion defect (ie, com Anatomy of the endocardial cushion defect (ie, complete form); note the common atrioventricular valve straddling the atrial septal and ventricular septal defects.

AV canal defects arise from abnormal development of the endocardial cushions. In these patients, the superior and inferior cushions do not close completely. An interatrial communication is left at the lower portion of the atrial septum. This is called an ostium primum defect. The failure of the endocardial cushions to fuse results in an abnormally low position of the AV valves and an abnormally high position of the aortic valve. A portion of the AV valves originates from the endocardial cushions, and their improper fusion results in anterior and posterior components to the mitral valve leaflet.[1]

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Pathophysiology

Predominant left-to-right shunting of blood through the heart occurs in these patients. In patients with partial defects, this occurs through the ostium primum atrial septal defect. When a complete endocardial cushion defect is present, a large ventricular septal defect as well as valvular insufficiency may develop, resulting in volume overload of both the left and right ventricles associated with heart failure in early life. In patients with long-standing pulmonary overload, pulmonary vascular disease may develop and congestive heart failure (CHF) symptoms may improve. This improvement is a poor prognostic indicator because it heralds the development of right-to-left shunting and irreversible pulmonary hypertension (ie, Eisenmenger syndrome).[2]

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Epidemiology

Frequency

United States

The frequency rate is about 3% of children with congenital heart disease. Sixty to seventy percent of these defects are of the complete form. More than half of those affected with the complete form have Down syndrome.

International

The frequency rate is about 3% of children who have congenital heart disease. Data from a Canadian study indicated that by 2010, adults accounted for two thirds of patients with congenital heart disease in the general population.[3]

Mortality/Morbidity

Patients with only ostium primum atrial septal defect and minimal insufficiency of the left AV valve (ie, mitral valve) do well without treatment during infancy, childhood, and adolescence. During adulthood, these patients develop symptoms of CHF and atrial arrhythmia.

Patients with septal defects and mitral valve insufficiency develop CHF early in life, with high rates of morbidity and mortality if the valvular insufficiency is pronounced. Patients with a complete defect develop CHF in infancy, with frequent respiratory infections and poor weight gain.

The American Heart Association issued recommendations intended to optimize the neurodevelopmental outcomes of children with congenital heart disease.[4] The recommendations included (1) using the medical home model of care to manage children with chronic conditions (eg, congenital heart disease) and to stratify them by risk (low and high) for neurodevelopmental disorder/disability at every medical home visit; (2) following the AAP guidelines for screening/surveillance, evaluation, and intervention in children with congenital heart disease; and (3) referral for patients at high risk of neurodevelopmental disorder/disability to formal developmental and medical evaluation as well as early intervention/childhood special education services.[4]

Race

No racial predilection is apparent.

Sex

Girls are affected slightly more frequently than boys.

Age

Endocardial cushion defect is a congenital defect present at birth. The severity of the symptom complex and presentation is dependent directly upon the severity of the defect and the presence of mitral insufficiency.

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Contributor Information and Disclosures
Author

Mary C Mancini, MD, PhD, MMM Professor and Chief of Cardiothoracic Surgery, Department of Surgery, Louisiana State University School of Medicine in Shreveport

Mary C Mancini, MD, PhD, MMM is a member of the following medical societies: American Association for Thoracic Surgery, American College of Surgeons, American Surgical Association, Society of Thoracic Surgeons, Phi Beta Kappa

Disclosure: Nothing to disclose.

Coauthor(s)

Henry G Hanley, MD Chief of Cardiology Section, Freedman Memorial Cardiology; Professor, Department of Medicine, Louisiana State University Health Sciences Center

Henry G Hanley, MD is a member of the following medical societies: American College of Cardiology, Society for Cardiovascular Angiography and Interventions, American College of Physicians, American Heart Association

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Frank M Sheridan, MD 

Frank M Sheridan, MD is a member of the following medical societies: American College of Cardiology, American Heart Association, Society for Cardiovascular Angiography and Interventions

Disclosure: Nothing to disclose.

Chief Editor

Park W Willis IV, MD Sarah Graham Distinguished Professor of Medicine and Pediatrics, University of North Carolina at Chapel Hill School of Medicine

Park W Willis IV, MD is a member of the following medical societies: American Society of Echocardiography

Disclosure: Nothing to disclose.

Additional Contributors

Park W Willis IV, MD Sarah Graham Distinguished Professor of Medicine and Pediatrics, University of North Carolina at Chapel Hill School of Medicine

Park W Willis IV, MD is a member of the following medical societies: American Society of Echocardiography

Disclosure: Nothing to disclose.

References
  1. Person AD, Klewer SE, Runyan RB. Cell biology of cardiac cushion development. Int Rev Cytol. 2005. 243:287-335. [Medline].

  2. Cooper RS. Endocardial cushion defects: embryology, anatomy and pathophysiology. Adv Cardiol. 2004. 41:118-26. [Medline].

  3. Marelli AJ, Ionescu-Ittu R, Mackie AS, Guo L, Dendukuri N, Kaouache M. Lifetime prevalence of congenital heart disease in the general population from 2000 to 2010. Circulation. 2014 Aug 26. 130(9):749-56. [Medline].

  4. [Guideline] Marino BS, Lipkin PH, Newburger JW, Peacock G, Gerdes M, Gaynor JW, et al. Neurodevelopmental outcomes in children with congenital heart disease: evaluation and management: a scientific statement from the American Heart Association. Circulation. 2012 Aug 28. 126(9):1143-72. [Medline].

  5. Tardif JC, Schwartz SL, Vannan MA, et al. Clinical usefulness of multiplane transesophageal echocardiography: comparison to biplanar imaging. Am Heart J. 1994 Jul. 128(1):156-66. [Medline].

  6. Weyman AE, Wann LS, Caldwell RL, et al. Negative contrast echocardiography: a new method for detecting left-to-right shunts. Circulation. 1979 Mar. 59(3):498-505. [Medline].

  7. Williams RG, Rudd M. Echocardiographic features of endocardial cushion defects. Circulation. 1974 Mar. 49(3):418-22. [Medline].

  8. Holmvang G, Palacios IF, Vlahakes GJ, et al. Imaging and sizing of atrial septal defects by magnetic resonance. Circulation. 1995 Dec 15. 92(12):3473-80. [Medline].

  9. Jacobstein MD, Fletcher BD, Goldstein S, Riemenschneider TA. Evaluation of atrioventricular septal defect by magnetic resonance imaging. Am J Cardiol. 1985 Apr 15. 55(9):1158-61. [Medline].

  10. Hanley FL, Fenton KN, Jonas RA, et al. Surgical repair of complete atrioventricular canal defects in infancy. Twenty-year trends. J Thorac Cardiovasc Surg. 1993 Sep. 106(3):387-94; discussion 394-7. [Medline].

  11. Prêtre R, Dave H, Kadner A, Bettex D, Turina MI. Direct closure of the septum primum in atrioventricular canal defects. J Thorac Cardiovasc Surg. 2004 Jun. 127(6):1678-81. [Medline].

  12. Silverman N, Levitsky S, Fisher E, et al. Efficacy of pulmonary artery banding in infants with complete atrioventricular canal. Circulation. 1983 Sep. 68(3 Pt 2):II148-53. [Medline].

  13. Studer M, Blackstone EH, Kirklin JW, et al. Determinants of early and late results of repair of atrioventricular septal (canal) defects. J Thorac Cardiovasc Surg. 1982 Oct. 84(4):523-42. [Medline].

 
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Anatomy of the endocardial cushion defect (ie, complete form); note the common atrioventricular valve straddling the atrial septal and ventricular septal defects.
Repair of the endocardial cushion defect. The patch is covering the ostium primum atrial septal defect.
 
 
 
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