<unk> s is a congenitial disorder most commonly associated with Down's syndrome. They are part of AV canal disorder resulting due to either genetic mutations or alteration in growth hormone in fetus leading to cardiac malformation during embryogenesis. Based on the anatomical features and their impact on physiology,<unk>  may be classified into complete, partial, intermediate, transitional, and intermediate forms. AV canal connects the atria to the ventricles. At four to five weeks of gestation, the superior and inferior<unk><unk> s of the common AV canal fuse. Results in the formation of the mitral and tricuspid valve and the AV septum. Any failure of fusion results in<unk> . Pathophysiology of<unk> s depends upon level of left to right shunting and degree of shunting. Incompetent AV valves in<unk>  results in regurgitation.<unk> s are transmitted in families as an autosomal dominant. The characteristic pattern of genetic mutation has been attributed to trisomy 21 and Down syndrome. The blowing holosystolic murmur of<unk> s must be distinguished from mitral regurtitaion, tricuspid regurgitation and a ventricular septal defect. Though ECG and chest x-ray may share some common features, echocardiography can be efficiently used for an accurate diagnosis. The prevalence of<unk>  is approximately 300 to 400 per 1000,000 live births. Certain factors might increase risk of developing<unk>  include down syndrome, rubella, alcohol consumption during pregnancy, gestational diabetes, smoking during pregnancy. Routine fetal ultrasound during prenatal care can detect<unk> s. Diagnostic findings on fetal ultrasound suggestive of<unk>  include large defect at the crux of the heart that involves the atrial and ventricular septa and a large common AV valve. If left untreated, majority of patients with<unk>  may progress to develop life threatening conditions. Common complications of<unk>  include dilatation of heart,  pulmonary hypertension, respiratory tract infections , and heart failure. Surgical mortality rate of patients with partial<unk>  is approximately 0.6%. For complete<unk>  defect the surgical mortality rate is 2.5-9%. Prognosis of<unk>  is generally good with treatment. However, some children might develop valvular and rhythm disorders after surgical correction. Echocardiography can be helpful in the diagnosis of<unk> . Findings on an echocardiography diagnostic of<unk>  include diastolic movement of the mitral valve with paradoxical motion of the interventricular septum. Other findings on echocardiography include absence of the interventricular septum and right ventricular dilation. The majority of patients with<unk>  are asymptomatic. Symptoms of<unk>  include chronic upper respiratory tract infections, pneumonia, and poor growth attributable to feeding difficulties. Patients with<unk>  may have a positive history of difficulty with crying, frequent pauses during feeding and nasal flaring. Volume overload of the right side of heart can lead to right heart failure that may present with symptoms of swelling of the extremities, difficulty breathing and signs such as hepatomegaly and an elevated jugular venous pulse. On cardiovascular examinations there is a fixed splitting of second heart sound. Also, a systolic ejection murmur that is attributed to the increased flow of blood through the pulmonic valve can be heard. Patients with<unk>  may have polycythemia on CBC, which is usually due to cyanosis. Presence of a superior axis directed more towards the left is the most characterstic feature of<unk> s on electrocardiogram. Other findings on a ECG suggestive of<unk>  include prolongation of PR interval and right ventricular enlargement. The management of<unk>  depends upon the type of defect, underlying etiology and associated cardiac conditions. Surgical correction of defective valve holds the the mainstay of treatment for<unk><unk> . Medical management provides supportive care in preparing the patient for surgery. The management of<unk>  depends upon the type of defect, underlying etiology and associated cardiac conditions. Surgical correction of defective valve holds the the mainstay of treatment for<unk><unk> . Medical management provides supportive care in preparing the patient for surgery. Effective measures for the secondary prevention of<unk> s include annual cardiology evaluation, routine neurological screening, infective endocarditis prophylaxis, and risk assessment during pregnancy.
Endocardial cushion defect
Atrioventricular canal defect
Deviated septum
Perforated septum
Interrupted aortic arch
Aortic arch anomalies
Atrioventricular septal defect
Ventricular septal defect