FFinalistSouthampton · 2027
Child health
AKT · Child health/Congenital heartlow yield

Atrioventricular septal defect (AVSD)

Defect of the central AV septum + common AV valve (strongly Down-syndrome associated)

Overview

A defect of the central crux of the heart — the atrioventricular septum and AV valves — ranging from partial (primum ASD + cleft mitral valve) to complete (a common AV valve with an atrial and ventricular component). Strongly associated with DOWN SYNDROME. Complete AVSD causes early heart failure and pulmonary hypertension; detected on antenatal/newborn screening and needs surgical repair.

Recognise

  • Often a Down-syndrome infant; complete AVSD → heart failure in infancy (breathlessness, faltering growth), pulmonary hypertension
  • May be detected antenatally or on the newborn check/pulse oximetry; superior axis on ECG
  • Mixed murmur; cyanosis if pulmonary hypertension/shunt reversal

Red flags

  • Heart failure + early pulmonary hypertension (complete AVSD) → timely surgical repair
  • Down syndrome → screen all with echocardiography

Differentials & how to tell them apart

Isolated VSD/ASDAVSD is the combined central defect with AV-valve involvement and a superior axis
Other Down-associated CHDVSD, ASD, ToF — echo defines

Investigations

Echocardiography (the AV septal defect, common valve); ECG (superior/left axis); part of Down-syndrome cardiac screening.

Management

Heart-failure management then surgical repair (early for complete AVSD)

  1. 1Echocardiography (all Down-syndrome infants are screened). Manage heart failure medically, then surgical repair.Gate: All infants with Down syndrome need cardiac screening because AVSD (and other CHD) is common; complete AVSD must be repaired before fixed pulmonary hypertension develops
  2. 2Surgical repair of the septal defect and AV valves; manage pulmonary hypertension; lifelong follow-up.
Diuretics ± ACE inhibitor + high-calorie feeds — medical management of heart failure pre-surgery
Surgical repair — definitive — within the first months for complete AVSD

Key points

Down syndrome + heart failure + superior axis = AVSD. Screen every Down-syndrome baby with echo. Complete AVSD → early surgery before pulmonary hypertension.

Monitor & prognosis

Heart failure, pulmonary pressures, surgical outcome.

Good with timely repair.

Source: RCPCH; Down syndrome cardiac screening