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Endocardial cushion defects

Updated : December 29, 2023





Background

  • Endocardial cushion defects (ECDs) refer to a group of congenital heart abnormalities that affect the endocardial cushions, structures in the developing heart that contribute to the formation of the atrial septum, ventricular septum, and atrioventricular (AV) valves. These defects arise during fetal development when the heart is forming and can lead to structural abnormalities that impact the normal flow of blood within the heart. Endocardial cushion defects are often associated with a spectrum of heart conditions, including atrial septal defects (ASD), ventricular septal defects (VSD), and abnormalities in the AV valves, such as the mitral and tricuspid valves. 
  • The background of endocardial cushion defects is closely tied to abnormal embryonic development. The endocardial cushions play a crucial role in partitioning the heart into its chambers and ensuring the proper alignment and function of the heart valves. When there is a failure in the fusion, formation, or positioning of these cushions, it can result in a range of structural defects. The most common form of ECD is known as atrioventricular septal defect (AVSD), characterized by a combination of ASD and VSD, along with abnormalities in the AV valves. 
  • Genetic factors and chromosomal abnormalities, particularly trisomy 21 (Down syndrome), are frequently associated with the development of endocardial cushion defects. Individuals with endocardial cushion defects may experience a variety of symptoms, including fatigue, difficulty breathing, and poor growth. Timely diagnosis and intervention are crucial for managing these defects, and treatment often involves surgical correction to restore normal cardiac function and improve long-term outcomes.  

Epidemiology

  • Incidence: Endocardial cushion defects represent a minority of congenital heart defects, occurring in 3% to 6% of individuals with congenital heart disease. The incidence can vary among different populations and ethnic groups. 
  • Association with Down Syndrome: There is a strong association between endocardial cushion defects and Down syndrome (trisomy 21). Up to 40% of individuals with Down syndrome have congenital heart defects, and ECDs, including atrioventricular septal defects (AVSD), are common in this population. 
  • Genetic Factors: These factors play a role in the development of endocardial cushion defects. Besides Down syndrome, there may be associations with other chromosomal abnormalities and genetic syndromes. 
  • Gender Differences: Some studies suggest a slight predilection for females in the occurrence of endocardial cushion defects. However, this gender difference may not be consistently observed across all populations. 
  • Race and Ethnicity: The prevalence of endocardial cushion defects can vary among different racial and ethnic groups. Some populations may have a higher or lower incidence of these defects. 
  • Family History: A family history of congenital heart defects may increase the risk of endocardial cushion defects in subsequent generations, indicating a potential genetic predisposition. 
  • Improved Detection through Prenatal Screening: Advances in prenatal screening and diagnostic techniques, such as fetal echocardiography, have led to improved detection of congenital heart defects, including endocardial cushion defects, during pregnancy. 

 

Anatomy

Pathophysiology

  • Embryonic Heart Development: During embryonic heart development, the heart tube undergoes complex morphological changes to form the four-chambered heart. The endocardial cushions, which are mesenchymal structures, play a crucial role in partitioning the atria and ventricles and in the formation of the atrioventricular (AV) valves. 
  • Endocardial Cushion Formation: The endocardial cushions form at the atrioventricular canal, where the septa and valves are developing. Proper fusion, growth, and positioning of these cushions are essential for the normal separation of the atria and ventricles and the formation of the AV valves. 
  • Failure of Fusion and Overgrowth: In cases of endocardial cushion defects, there is a failure of complete fusion of the endocardial cushions, leading to persistent openings between the atria and ventricles. This failure results in abnormal communication between the heart chambers. 
  • Atrioventricular Septal Defect (AVSD): The most common form of endocardial cushion defect is AVSD, characterized by a combination of atrial septal defect (ASD) and ventricular septal defect (VSD). In addition to the septal defects, there is often abnormal formation of the AV valves, leading to a common AV valve instead of distinct mitral and tricuspid valves. 
  • Shunting of Blood: The presence of septal defects allows for abnormal shunting of blood between the atria and ventricles, as well as between the left and right ventricles. This results in increased blood flow to lungs, leading to pulmonary over circulation. 
  • Hemodynamic Consequences: The abnormal shunting and hemodynamic consequences may lead to volume overload in the heart chambers and increased pulmonary blood flow. Over time, this can result in pulmonary hypertension and, if left untreated, may lead to complications such as heart failure. 
  • Associated Anomalies: The pathophysiology may involve additional associated anomalies, such as abnormal positioning or attachment of the papillary muscles, which further contribute to valvular dysfunction and regurgitation. 

Etiology

  • Chromosomal Abnormalities: ECDs are strongly associated with chromosomal abnormalities, particularly trisomy 21 (Down syndrome). They may have an increased risk of congenital heart defects, and AVSD (atrioventricular septal defect), a form of ECD, is commonly observed in this population. 
  • Maternal Diabetes: Maternal diabetes, especially when poorly controlled during pregnancy, has been identified as a potential environmental risk factor for congenital heart defects, including ECDs. Elevated blood glucose levels may interfere with normal embryonic development. 
  • Teratogenic Exposures: Exposure to certain teratogenic agents or environmental factors during pregnancy, like certain medications or infections, may increase the risk of congenital heart defects. However, specific agents linked directly to ECDs are not always clearly identified. 
  • Genetic Syndromes: Some genetic syndromes with cardiovascular implications, beyond chromosomal anomalies, may increase the risk of ECDs. Examples include Holt-Oram syndrome and Ellis-van Creveld syndrome. 
  • Family History: There is an increased risk of ECDs in families with a history of congenital heart defects. Individuals with affected siblings or parents may have a higher likelihood of experiencing ECDs themselves. 
  • Hemodynamic Changes: Abnormal blood flow patterns during early heart development may influence the development of endocardial cushions. Disturbed hemodynamic can contribute to cushion malformation, especially in the context of genetic susceptibility. 

 

Genetics

Prognostic Factors

  • Type and Severity of the Defect: The specific type and severity of the endocardial cushion defect, such as the presence and size of atrial and ventricular septal defects, influence the overall prognosis. Atrioventricular septal defects (AVSDs), a common type of ECD, may vary in complexity, affecting the prognosis. 
  • Presence of Associated Cardiac Anomalies: The presence of additional cardiac anomalies, beyond the endocardial cushion defect, can impact prognosis. The involvement of other structures or valves may contribute to a complex clinical picture and affect long-term outcomes. 
  • Genetic Syndromes and Chromosomal Abnormalities: The association of endocardial cushion defects with genetic syndromes, particularly trisomy 21 (Down syndrome), can influence the prognosis. The presence of a genetic syndrome may be associated with additional health challenges and developmental concerns. 
  • Early Diagnosis and Intervention: The early diagnosis and timely intervention can improve the prognosis for individuals with ECDs. Prenatal detection through advanced imaging techniques and prompt medical and surgical management can positively impact outcomes. 
  • Surgical Correction: The timing and success of surgical correction play a crucial role in prognosis. Individuals who undergo surgical repair to address the endocardial cushion defect and associated anomalies may experience improved cardiac function and quality of life. 
  • Pulmonary Hypertension: It is a potential complication of ECDs. The degree of pulmonary hypertension and its response to treatment can influence the long-term prognosis. 
  • Cardiac Function and Hemodynamic: The overall cardiac function and hemodynamic status, including the ability of the heart to pump blood effectively and the presence of valvular regurgitation, contribute to prognosis. 
  • Postoperative Complications: The occurrence of postoperative complications, such as arrhythmias or residual septal defects, can impact the prognosis. Close monitoring and appropriate management are essential in the postoperative period. 
  • Growth and Developmental Milestones: Growth and developmental milestones, both physical and cognitive, are important indicators of overall well-being. Adequate nutrition, developmental support, and early intervention services may influence the long-term prognosis. 

 

Clinical History

Age: 

  • Neonatal and Infancy: Endocardial cushion defects often present in the neonatal or early infancy period. 
  • Children and Adolescents: Diagnosis and management may continue into childhood and adolescence. 

Physical Examination

  • General Appearance: Evaluate the general appearance for signs of distress, such as difficulty feeding, lethargy, or irritability. 
  • Cyanosis: Assess for central or peripheral cyanosis, which may indicate inadequate oxygenation. 
  • Respiratory Rate: Measure the respiratory rate, as increased respiratory effort may be a sign of respiratory distress. 
  • Heart Sounds: Auscultate heart sounds to identify murmurs or abnormal sounds associated with the endocardial cushion defect. 
  • Growth and Development: Monitor growth parameters and assess developmental milestones, as failure to thrive or developmental delays may be indicative of cardiovascular compromise. 
  • Pulses: Assess peripheral pulses to evaluate for signs of poor perfusion. 
  • Cardiovascular System: Evaluate the cardiovascular system, including palpation of the precordium for heaves or thrills. 
  • Peripheral Edema: Check for signs of peripheral edema, which may be indicative of right-sided heart failure. 
  • Pulmonary Examination: Assess lung fields for crackles or evidence of pulmonary congestion. 
  • Clubbing of Fingers: In severe cases, clubbing of fingers may be observed. 
  • Liver Enlargement: Palpate the liver for enlargement, as right-sided heart failure can lead to hepatic congestion. 

Age group

Associated comorbidity

  • Down Syndrome: There is a significant association between ECDs and Down syndrome. A considerable proportion of individuals with ECDs have trisomy 21. 
  • Other Chromosomal Abnormalities: In addition to Down syndrome, other chromosomal abnormalities may be associated with ECDs. 
  • Pulmonary Hypertension: Over time, individuals with uncorrected ECDs may develop pulmonary hypertension due to increased blood flow to the lungs. 

Associated activity

Acuity of presentation

  • Neonatal Presentation: Many individuals with ECDs present in the neonatal period with symptoms such as cyanosis, respiratory distress, and failure to thrive. 
  • Developmental Milestones: Delayed developmental milestones may be observed in some cases, especially in individuals with associated chromosomal abnormalities. 
  • Recurrent Respiratory Infections: Due to increased blood flow to the lungs, individuals may be prone to recurrent respiratory infections. 
  • Heart Failure Symptoms: As the defect progresses, symptoms of heart failure, such as fatigue, difficulty feeding, and poor weight gain, may become evident. 
  • Cardiac Murmurs: A characteristic heart murmur may be detected upon physical examination.  

Differential Diagnoses

  • Atrial Septal Defect (ASD): ASDs involve a defect in the atrial septum, allowing shunting of blood between the atria. While ECDs may include an ASD component, isolated ASDs are distinct from the more complex anatomical abnormalities seen in ECDs. 
  • Ventricular Septal Defect (VSD): Isolated VSDs involve a defect in the ventricular septum without the associated abnormalities in the atrioventricular (AV) valves seen in ECDs. 
  • Patent Ductus Arteriosus (PDA): PDA is a congenital heart condition where the ductus arteriosus, a fetal blood vessel, fails to close after birth, leading to abnormal shunting of blood between the aorta and pulmonary artery. It may share some symptoms with ECDs. 
  • Pulmonary Stenosis or Atresia: Conditions affecting the pulmonary valve or pulmonary artery may present with symptoms such as cyanosis and respiratory distress, resembling certain presentations of ECDs. 
  • Tricuspid Valve Abnormalities: Isolated tricuspid valve abnormalities, such as tricuspid regurgitation or stenosis, may have similar clinical features but are not part of the specific complex defect seen in ECDs. 
  • Ebstein’s Anomaly: It is a congenital heart defect affecting the tricuspid valve and right ventricle. While it can share symptoms such as cyanosis and heart failure, it is a separate entity. 
  • Congenital Heart Block: Congenital heart block can present with bradycardia and may be associated with maternal autoimmune conditions. It is distinct from ECDs but may require evaluation by a pediatric cardiologist. 
  • Left-to-Right Shunt Lesions: Other congenital heart defects with left-to-right shunting, such as atrioventricular septal defects (AVSDs), may resemble ECDs in terms of symptoms but have different anatomical features. 
  • Acquired Valvular Disease: Conditions such as infective endocarditis or rheumatic heart disease can lead to acquired abnormalities in the atrioventricular valves, but these are not congenital defects. 
  • Vascular Ring: Certain vascular anomalies, like a vascular ring, may cause respiratory and feeding difficulties in neonates and could be considered in the differential diagnosis. 

 

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

  • Medical Management: In the neonatal period or when symptoms are severe, medical management focuses on stabilizing the infant. This may include oxygen therapy, diuretics to reduce fluid overload, and medications to support cardiac function. 
  • Surgical Correction: Definitive treatment for ECDs often involves surgical repair. The timing of surgery depends on clinical presentation, severity of symptoms, and the specific anatomy of the defect. Surgical correction aims to close septal defects, reconstruct valves, and restore normal cardiac anatomy. 
  • Genetic Evaluation and Counseling: Given the association of ECDs with genetic syndromes, genetic evaluation and counseling may be recommended. Understanding the genetic component can guide family planning decisions and provide insights into potential associated health issues. 
  • Postoperative Care: After surgical correction, individuals require postoperative care and monitoring to assess recovery, address potential complications, and optimize long-term outcomes. 
  • Long-Term Follow-Up: Lifelong cardiac follow-up is essential for individuals with ECDs. Regular check-ups help monitor cardiac function, assess for late complications, and address any residual issues or the need for additional interventions. 
  • Reproductive Counseling: For individuals of reproductive age, reproductive counseling may be provided to address potential risks during pregnancy and the likelihood of passing on the condition to offspring. 
  • Multidisciplinary Support: A multidisciplinary team, including pediatric cardiologists, cardiac surgeons, genetic counselors, and other specialists, collaborates to provide comprehensive care throughout the individual’s lifespan. 
  • Patient and Family Education: Patient and family education is crucial to ensure a clear understanding of the condition, treatment options, and the importance of ongoing medical care. This empowers individuals and their families to actively participate in managing their health. 
  • Adaptation of Lifestyle: Lifestyle modifications may be recommended based on individual needs and the presence of any residual issues. These may include dietary considerations, exercise recommendations, and precautions to minimize the risk of complications. 

 

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

non-pharmacological treatment of Endocardial cushion defects

Lifestyle modifications: 

  • Healthy Diet: A balanced diet including vegetables, whole grains, fruits, and lean proteins. Limit sodium intake to manage fluid balance and reduce the risk of fluid retention. 
  • Avoidance of Smoking and Tobacco: Refrain from smoking and avoid second hand smoke exposure, as smoking can contribute to cardiovascular complications. 
  • Stress Management: Incorporate techniques such as relaxation exercises, mindfulness, or yoga to promote mental well-being. 
  • Regular Sleep Patterns: Maintain regular sleep patterns and ensure an adequate amount of sleep each night. 
  • Medication Adherence: Adhere to prescribed medications as directed by healthcare providers to manage symptoms and optimize cardiac function. 
  • Hydration: Maintain proper hydration, especially if diuretics are part of the treatment plan. 
  • Avoidance of Overexertion: Be cautious not to overexert oneself and recognize personal limits during physical activities. 
  • Reproductive Counselling: For individuals of childbearing age, seek reproductive counselling to discuss potential risks during pregnancy and family planning. 
  • Dental Care: Maintain good oral hygiene and inform dental healthcare providers about the heart condition before dental procedures. 
  • Psychosocial Support: Seek and maintain a strong support system, including friends, family, and support groups, to address emotional and psychological aspects. 

 

use of Diuretics in the treatment of Endocardial cushion defects

Diuretics, including furosemide, may be used in the treatment of endocardial cushion defects (ECDs) to manage symptoms associated with fluid overload and congestion. ECDs often lead to increased blood flow to the lungs and can result in pulmonary congestion, contributing to shortness of breath and respiratory distress. Diuretics help alleviate these symptoms by promoting the excretion of excess fluid and reducing the overall volume of circulating blood. Here is how diuretics, particularly furosemide, are used in the context of ECDs: 

Use of Furosemide (Diuretic): 

  • Reduction of Fluid Overload: Furosemide acts on loop of Henle in the kidneys, promoting excretion of sodium and water. By increasing urine production, furosemide helps reduce fluid overload in the body, including pulmonary congestion. 
  • Management of Edema: Edema, often seen in individuals with heart failure and ECDs, involves the accumulation of fluid in tissues. Furosemide helps reduce edema by eliminating excess fluid through increased urine output. 
  • Symptomatic Relief: Individuals with ECDs may experience symptoms such as shortness of breath and fatigue due to fluid accumulation in the lungs and other tissues. Furosemide provides symptomatic relief by addressing fluid-related symptoms. 
  • Adjustment Based on Clinical Response: The dosage and frequency of furosemide administration are often adjusted based on the individual’s clinical response and the severity of symptoms. Regular monitoring of electrolyte levels, especially potassium, is essential, as diuretics can lead to electrolyte imbalances. 

use of Inotropic agents in the treatment of Endocardial cushion defects

Inotropic agents, including digoxin, may be used in the treatment of endocardial cushion defects (ECDs) to support cardiac function and manage symptoms associated with heart failure. ECDs often result in abnormal blood flow patterns and compromised cardiac output, leading to symptoms such as fatigue, poor feeding, and respiratory distress. Inotropic agents, which enhance the force of cardiac muscle contractions, can be beneficial in certain cases. Here is how digoxin is used in the context of ECDs: 

Use of Digoxin (Inotropic Agent): 

  • Enhancement of Cardiac Contractility: Digoxin is a positive inotropic agent that increases the force of myocardial contractions, improving the efficiency of the heart’s pumping action. This enhancement in contractility can help maintain cardiac output in individuals with ECDs, especially when there is impaired ventricular function. 
  • Control of Heart Rate: Digoxin also has a mild negative chronotropic effect, meaning it can reduce the heart rate. In some cases of ECDs, especially when there are associated arrhythmias, digoxin can help control heart rate and improve overall cardiac function. 
  • Management of Fluid Retention: Digoxin’s positive inotropic effects contribute to better circulation and may help manage fluid retention by improving the pumping efficiency of the heart. 
  • Combination with Diuretics: Digoxin is often prescribed in combination with diuretics (e.g., furosemide) to address both the contractility of the heart and fluid balance in the body. 

mitral valvuloplasty of Endocardial cushion defects

  • Mitral valvuloplasty and closure of atrial septal defect (ASD) are surgical interventions that may be considered in the comprehensive treatment of endocardial cushion defects (ECDs). ECDs involve complex anatomical abnormalities, including atrial and ventricular septal defects and abnormalities of the atrioventricular (AV) valves.  
  • Mitral Valvuloplasty: 
  • Objective: Mitral valvuloplasty focuses on addressing abnormalities in the mitral valve, which is often affected in ECDs. The valve may be malformed or have issues with leaflet closure. 
  • Surgical Techniques: Repair techniques may include reshaping the mitral valve leaflets, reinforcing the valve with patches, or addressing chordal abnormalities. The goal is to improve valve function and prevent regurgitation (backflow of blood) through the mitral valve. 
  • Preservation of Valve Tissue: Whenever possible, surgeons aim to preserve the patient’s own valve tissue to maintain long-term valve function. 
  • Reduction of Regurgitation: Mitral valvuloplasty is designed to reduce or eliminate mitral regurgitation, which is common in individuals with ECDs. 
  • Individualized Approach: The surgical approach is tailored to the specific anatomy of the patient’s mitral valve and the extent of valvular abnormalities. 
  • Closure of Atrial Septal Defect 
  • Objective: Atrial septal defects, which are often present in ECDs, involve communication between the atria. Closure of the atrial septal defect is a crucial aspect of surgical intervention. 
  • Techniques: Closure may involve direct suturing of the defect or the use of patches to close the hole in the atrial septum. 
  • Prevention of Shunting: Closing the atrial septal defect helps prevent abnormal shunting of blood between the atria, allowing for more normal blood flow patterns. 
  • Improvement of Hemodynamics: By correcting the atrial septal defect, surgeons aim to improve hemodynamics and reduce the impact on overall cardiac function. 

management of Endocardial cushion defects

  • Acute Phase: 
  • Diagnosis and Evaluation: Rapid and accurate diagnosis through echocardiography, cardiac catheterization, and other imaging studies. Assessment of the severity of the defect and its impact on cardiac function. 
  • Stabilization: Initial management focuses on stabilizing the patient, especially in neonatal cases or when symptoms are severe. Oxygen therapy may be administered to address hypoxemia.