What is an Endocardial Cushion Defect?

An endocardial cushion defect (ECD), also known as atrioventricular (AV) canal defect, is a congenital heart condition characterized by lack of a wall separating chambers of the heart. Treatment for this condition involves the surgical closure of the holes present between heart chambers and may require more than one surgical procedure to complete. If left untreated, there are serious complications associated with an ECD that may include congestive heart failure and death.

A fetus can develop an endocardial cushion defect while in utero. The endocardial cushions are walls that separate the heart's four chambers and form the tricuspid and mitral valves. When these walls fail to develop, several serious complications may develop that adversely affect lung and heart function. An endocardial cushion defect may manifest in one of two ways: either partially or completely.

A partial presentation of an endocardial cushion defect occurs when there is an atrial septal defect (ASD) and one of the heart's two valves develops abnormally. When a partial ECD occurs, the mitral valve is impaired, allowing blood to seep between chambers located on the left side of the heart muscle. A complete presentation of ECD involves an ASD and a ventricular septal defect (VSD). Those diagnosed with complete ECD have a single, large heart valve instead of two separate, normal size valves.

A lack of separation between the heart's chambers may contribute to the development of elevated blood pressure and inflammation within the lungs. The heart's functionality becomes impaired, requiring it to work overtime, and, as a result, the heart may become enlarged and weaken. Due to the adverse effects of ECD on the lungs and heart, the entire body becomes oxygen-deprived.

Children born with an ECD may exhibit a variety of signs and symptoms. An infant who is easily fatigued, whose skin has a bluish tint, or experiences breathing difficulty may have an endocardial cushion defect. A child who frequently acquires pneumonia or is unable to gain weight may also be symptomatic. Additional signs of ECD may include a distention of the abdomen or extremities, elevated heartbeat and breathing, and a loss of appetite.

Infants with a partial endocardial cushion defect who possess normally formed heart valves may remain asymptomatic, meaning they experience no symptoms, for several years. There are several tests utilized to diagnose ECD, including magnetic resonance imaging (MRI), ultrasound, and chest X-ray. Additional signs utilized to confirm a diagnosis of ECD may include the presence of a heart murmur and elevated blood pressure within the lungs.

Treatment for an ECD generally involves the surgical closure of the holes within the heart chambers. Valve reconstruction may also be conducted to create new mitral and tricuspid valves. The timing of corrective surgery for an ECD is dependent on the child’s condition and age. In most cases, the surgical correction of an ECD may require more than one procedure. Ideally, surgery should be conducted prior to the child’s first birthday to prevent the development of complications.

The overall prognosis associated with an endocardial cushion defect is dependent on the child’s overall health, the severity of his or her condition, and the condition of the child’s heart and lungs. With timely, appropriate treatment, children usually make a full recovery. Complications associated with an ECD may include irreversible lung damage, congestive heart failure, and death. In some cases, complication development may be delayed to adulthood and may include heart arrhythmias and mitral valve dysfunction. To prevent future, post-operative heart infections, it is recommended that children take an oral antibiotic prior to receiving any dental treatment or surgical procedures.