Endocardial Cushion Defects (Atrioventricular Canal Defects, Atrioventricular Septal Defects) Clinical Presentation

Updated: Dec 28, 2020
  • Author: Mary C Mancini, MD, PhD, MMM; Chief Editor: Yasmine S Ali, MD, MSCI, FACC, FACP  more...
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An infant with endocardial cushion defect (atrioventricular [AV] canal or septal defect) 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 congestive heart failure (CHF) may develop, including aversion to activity and play, easy fatigability, dyspnea, and edema.


Physical Examination

Partial endocardial cushion defects (atrioventricular [AV] canal or septal defects) present with the physical findings common to atrial septal defects (ASDs).

  • 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 (VSD) 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: (1) A single first heart sound is heard, which may be a relatively soft fixed splitting of the second heart sound. (2) A systolic murmur of a ventricular septal defect can be heard as well as the systolic murmur of mitral insufficiency. (3) Pulmonary hypertension is associated with a loud pulmonic component of the second heart sound.