Endocardial Cushion Defects Clinical Presentation

Updated: Sep 15, 2014
  • Author: Mary C Mancini, MD, PhD, MMM; Chief Editor: Park W Willis IV, MD  more...
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An infant may be relatively asymptomatic. In severe cases, patients have a history of poor feeding, chronic upper respiratory tract infections, pneumonia, and poor growth. The mother may notice difficulty with crying, frequent pauses during feeding, and nasal flaring. As the child grows older, the more common manifestations of CHF may develop, including aversion to activity and play, easy fatigability, dyspnea, and edema.



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  • Partial defects present with the physical findings common to atrial septal defects.

    • The second heart sound is widely split without respiratory variations.

    • A systolic ejection murmur may be heart at the upper left sternal border.

    • A low-pitched early diastolic rumble may be heart at the lower left sternal border and is related to increased tricuspid valve flow.

    • A murmur of mitral insufficiency may or may not be present.

  • Additional findings in complete endocardial cushion defects relate to the ventricular septal defect and valvular insufficiency.

    • Poor physical development, hyperinflated thorax, bulging precordium, Harrison grooves, mild or intermittent cyanosis, and stigmata of Down syndrome (eg, oblique palpebral fissures, large protuberant tongue, short and broad hands, simian crease, inner epicanthic skin fold)

    • Arterial and jugular venous pulse - Water hammer pulse, dominant v wave in the jugular venous pulse

    • Precordial movement and palpation - Systolic thrill, palpable impulse in the second and third intercostal space representing a dilated pulmonary artery, prominent heave at the left sternal border

    • Auscultation

      • A single first heart sound is heard, which may be a relatively soft fixed splitting of the second heart sound.

      • A systolic murmur of a ventricular septal defect can be heard as well as the systolic murmur of mitral insufficiency.

      • Pulmonary hypertension is associated with a loud pulmonic component of the second heart sound.



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  • Genetics

    • The characteristic pattern of the malformation has been attributed to trisomy 21 and Down syndrome in some cases. Some evidence exists that a critical region of chromosome band 21q22 may contribute particularly to the cardiac malformation in this syndrome.

    • Other chromosomal abnormalities also can result in AV septal defects, in particular, deletion of 8p, partial 10q monosomy, partial 13q monosomy, ring 22 14 q+, and 1p+3p-.

    • In most cases of significant chromosomal aberration, AV septal defects are associated with other noncardiac congenital defects. However, isolated AV septal defects can be transmitted in families as an autosomal dominant trait.

    • Linkage analyses have suggested a locus for autosomal dominant AV septal defects on chromosome 1p but no specific gene defect has yet been identified.

  • Growth factor aberrations: In the developing fetus, cardiac tissue formation is dependent upon appropriate growth factor stimulation including transforming growth factor beta and platelet-derived growth factor. Alterations in the concentration or efficacy of these factors during embryogenesis can contribute to the cardiac malformations.