Pediatric Unbalanced Atrioventricular Septal Defects Clinical Presentation

Updated: Jan 04, 2016
  • Author: Mark A Law, MD; Chief Editor: Howard S Weber, MD, FSCAI  more...
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Infants with unbalanced atrioventricular (AV) septal defects generally present in the first month of life with congestive heart failure (CHF) with tachypnea and failure to thrive due to pulmonary overcirculation, if no significant right-sided or left-sided obstruction is present.

If pulmonary outflow tract obstruction is present, infants may present with cyanosis or an audible murmur.

Occasionally, neonates may present in extremis with acidosis in the presence of ductal-dependent systemic circulation or cyanosis in the presence of ductal-dependent pulmonary circulation.

Patients with abdominal heterotaxy may present with situs inversus incidentally noted on routine chest radiography.



Note the following:

  • Most children appear healthy, except the rare patient with features of Down syndrome.

  • This lesion is associated with various auscultatory findings, depending on the underlying physiology.

  • Murmurs of pulmonary stenosis, left ventricular (LV) outflow tract obstruction, or atrioventricular valve (AVV) regurgitation may be appreciated. [9]

  • Cyanosis may be present.

  • Reduced lower extremity pulses may suggest coarctation of the aorta, which may coexist with right ventricle (RV)–dominant atrioventricular canal (AVC).



The genetic basis for this lesion has not been elucidated; however it can be associated with trisomy 21.

Unbalanced AV septal defect may be observed in patients with abdominal heterotaxy. The presence of complete AV septal defect is more than twice as frequent in patients with asplenia than in those with polysplenia.