An endocardial cushion defect, also known as the atrioventricular septal defect, encompasses several congenital heart disease forms of abnormal atrioventricular septation and formation of a single atrioventricular valve. Cyanosis is principally seen in milder forms, whereas congestive heart failure and even death may develop in more severe cases, especially if the condition is not recognized early on. Clinical workup and echocardiography, either prenatal or postnatal, are used to make the diagnosis.
Signs and symptoms of an endocardial cushion defect arise from a variable degree of blood shunting due to the absence of separate atrioventricular valves  . Instead, a common atrioventricular valve exists and is accompanied by a large atrial septal defect (ASD) and a ventricular septal defect (VSD), designated as complete endocardial cushion defect . On the other hand, partial (two atrioventricular orifices and the absence of an ASD) and intermediary (a markedly smaller VSD) forms have been described as well  . Regardless of the anatomical severity, initial left-to-right shunting due to increased pressures of the left heart will cause pulmonary hypertension and induce a simultaneous right-to-left shunting   . The bidirectional blood shunting in the heart is known as the Eisenmenger's syndrome, which leads to congestive heart failure in the majority of cases with a complete endocardial cushion defect . Tachycardia, tachypnea, poor peripheral circulation, feeding difficulties and excessive sweating are encountered in the first few months of life, and in the absence of an early diagnosis, 50% of infants will die during the first year of life   . In most severe cases, in whom marked regurgitation of the common AV valve and the presence of other anomalies further impede blood flow through the aorta, heart failure can develop as early as one week after delivery . Central and less commonly peripheral cyanosis are a frequent finding as well  .
Entire Body System
- Congestive Heart Failure
A small number of infants with a complete atrioventricular septal defect will not develop congestive heart failure. [cincinnatichildrens.org]
The clinical presentation of severe, intractable congestive heart failure in these neonatal patients would suggest the diagnosis of typical hypoplastic left heart syndrome. [ncbi.nlm.nih.gov]
Congestive heart failure: Left untreated, AVSD causes congestive heart failure, a condition in which the heart cannot pump enough blood to meet the body’s needs. [chd-uk.co.uk]
If the child is in congestive heart failure, there will be poor weight gain, the heart rate and breathing rate will be higher than normal, and the liver will be enlarged. [mottchildren.org]
- Trisomy 21
Indeed, Fredouille et al. reported that two-thirds of trisomy 21 fetuses had absence of AV valve offsetting without a septal defect during autopsy (24). [fetalultrasound.com]
She had severe pulmonary hypertension and suspected trisomy 21. [ncbi.nlm.nih.gov]
Associations trisomy 21 (Down syndrome) : may be present in up to 50% of cases 4 trisomy 18 (Edwards syndrome) : may be present in up to 25 % of cases 7 heterotaxy syndromes 7 may be present in up to 10% of cases of asplenia (Ivemark) syndrome 4 Plain [radiopaedia.org]
- Failure to Thrive
Surgical repair For heart failure, medical therapy (eg, diuretics, digoxin, ACE inhibitors) before surgery Complete atrioventricular septal defect should be repaired by age 2 to 4 mo because most infants have heart failure and failure to thrive. [merckmanuals.com]
It becomes symptomatic in infancy due to congestive heart failure and failure to thrive. Diagnosis of CAVC might be suspected from electrocardiographic and chest X-ray findings. Echocardiography confirms it and gives anatomical details. [doi.org]
Typical symptoms include tachypnea, increased work of breathing, and failure to thrive. These symptoms may be seen in other forms of congenital heart disease. There are no symptoms specific to AVSD. [clinicaladvisor.com]
• Failure to thrive.• Age at operation of 40. • In a series of 334 patients from Mayo Clinic, 20- and 40-year survivals after repair of partial AVSD were 87% and 76%, respectively.• Closure of the mitral cleft and age 41. • A low frequency of postoperative [slideshare.net]
- Heart Disease
International The frequency rate is about 3% of children who have congenital heart disease. [emedicine.com]
The first symptoms of previously undiagnosed congenital heart disease may become apparent during pregnancy. [ncbi.nlm.nih.gov]
Congenital heart disease in the adult and pediatric patient. In: Zipes DP, Libby P, Bonow RO, Mann DL, Tomaselli GF, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 11th ed. [mountsinai.org]
This causes cyanosis, or bluish skin. There are two types of ECD: Complete ECD. This condition involves an atrial septal defect (ASD) and a ventricular septal defect (VSD). [medlineplus.gov]
Even though one expects severe cyanosis in common AV canal, the intensity of which is primarily determined the net blood flow to lungs which is dictated by the pulmonary vascular resistance or the RVOT obstruction. [drsvenkatesan.com]
The defects can make the heart have to work harder to pump blood and cause symptoms like difficulty feeding, failure to gain weight, lung congestion, and a bluish tint to the skin (called cyanosis). [kidshealth.org]
- Heart Murmur
There is usually a heart murmur present, but it is softer than that which occurs with a complete atrioventricular septal defect. [cincinnatichildrens.org]
Children with AVSD usually have a heart murmur, which a healthcare provider can hear with a stethoscope. A heart murmur is an extra sound made between heartbeats. These murmurs are caused by the blood flowing abnormally through the heart. [drpachadharma.com]
Children with AVCD usually have a heart murmur, which a healthcare provider can hear with a stethoscope. A heart murmur is an extra sound made between heartbeats. The murmur is caused by the abnormal flow of blood through the heart. [summitmedicalgroup.com]
- Systolic Murmur
A cleft in the left AV valve results in a blowing apical systolic murmur of mitral regurgitation. [merckmanuals.com]
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. [chdbabies.com]
murmur at the apex of her heart. [ncbi.nlm.nih.gov]
- Gallop Rhythm
If a significant regurgitation of the common atrioventricular valve is present, a systolic cardiac murmur and gallop rhythm are frequently heard. [doi.org]
Due to the life-threatening risk in the very first weeks of life, the diagnosis of an endocardial cushion defect must be made promptly. Identification of a heart murmur (most likely pansystolic, but also ejection systolic or apical mid-diastolic) during cardiac auscultation can raise sufficient clinical suspicion toward heart disease in infants and neonates, especially if accompanying symptoms are present  . For this reason, the role of a proper physical examination is vital  . Plain radiography often reveals cardiomegaly and deviation of the cardiac axis, but electrocardiography (ECG) and more importantly, echocardiography should be immediately performed, with the latter being the gold standard in confirming the presence of a congenital heart disease (CHD), both prenatally and postnatally   . Direct imaging of the heart through ultrasonography will show a common atrioventricular valve and the absence of an atrioventricular septum, defects of the ventricular septal and atrial flow, as well as bi-directional blood flow on doppler ultrasonography   . Magnetic resonance imaging (MRI) of the heart has also proven to be a useful method for assessing the cardiac anomalies seen in endocardial cushion defect . Isolated studies have confirmed a very potent relationship of this CHD with Down syndrome, suggesting that a meticulous prenatal diagnostic workup is necessary for ensuring an early diagnosis, which will allow early therapy and reduction in mortality rates  .
- Left Axis Deviation
Abstract Three groups of patients are identified in the series of secumdum atrial septal defect with left axis deviation in an analysis of 910 patients of secundum atrial septal defect with or without other accompanying anomalies: 1) 12 patients with [ncbi.nlm.nih.gov]
axis deviation Biventricular hypertrophy Chest X-ray Cardiomegaly with increased pulmonary vascular markings Treatment Close the atrial and/or ventricular septal defects with patch material and repair the atrioventricular valves. [echocardiology.org]
Clinical features- See hemodynamics Radiography- See hemodynamics ECG- Left axis deviation Counterclockwise depolarization- as initial left to right septal depolarization does not occur Prolonged PR interval in about half cases- due to prolonged atrial [heartpearls.com]
Electrocardiography: Left axis deviation with a counterclockwise vector loop is common ( Figure 4 ). Prolongation of the PR and QRS intervals is also common. Figure 4. [clinicaladvisor.com]
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- Espinola-Zavaleta N, Muñoz-Castellanos L, Kuri-Nivón M, Keirns C. Understanding atrioventricular septal defect: Anatomoechocardiographic correlation. Cardiovasc Ultrasound. 2008;6:33.
- Calabrò R, Limongelli G. Complete atrioventricular canal. Orphanet J Rare Dis. 2006;1:8.
- Mureşan D, Mărginean C, Zaharie G, Stamatian F, Rotar IC. Complete atrioventricular septal defect in the era of prenatal diagnosis. Med Ultrason. 2016;18(4):500-507.
- Craig B. Atrioventricular septal defect: from fetus to adult. Heart. 2006;92(12):1879-1885.