Patent Ductus Arteriosus: The Ductus arteriosus (DA) is a fetal vascular connection between the main pulmonary artery and the aorta that diverts blood away from the lungs. After birth, the Ductus Arteriosus undergoes active constriction (closing) and eventual obliteration. A patent ductus arteriosus (PDA) occurs when the Ductus Arteriosus fails to completely close postnatally.
 

Aorta-Pulmonary window: An aortaopulmonary window results from incomplete develoment of the conotruncal (aorta-pulmonary) septum.
 

Coarctation of the Aorta: Aorta Coarctation is narrowing of the distal segment of the decending thoracic aorta leading to decreased blood flow to the abdominal organs and lower limbs. There is a wide range of presentation. The most significant presentation is as a neonate where the lower body are perfused through the ductus artriosus and coarctation becomes evident when the ductus artriosus undergoes natural closure. Coarctation of the aorta accounts for 4 to 6 percent of all congenital heart defects with a reported prevalence of about 4 per 10,000 live births. It occurs more commonly in males than in females (59 versus 41 percent). Most cases are sporadic.
 

Atrial Septal Defect: Atrial septal defects (ASDs) are communications between the two receiving chambers of the heart (atria). ASD's are common, accounting for approximately 13 percent of congenital heart disorders. The clinical consequences of an ASD are related to the anatomic location of the defect, its size, and the presence or absence of other cardiac anomalies. There are 5 types of ASD's and there hemodynamic impact and indication for surgery is similar.
 

Ventricular Septal Defect: The most common congenital heart lesion is ventricular septal defect (VSD). It occurs in almost 50 percent of all patients with congenital heart disease with a reported prevalence of 41.8 per 10,000 live births. VSDs occur in isolation or in combination with other congenital heart defects, as in an atrioventricular canal (AVC), tetralogy of Fallot (TOF) and occasionally, transposition of the great arteries (D-TGA). VSDs may occur at various locations in the ventricular septal components. The particular location of the defect has no bearing on the characteristics of the intracardiac shunt, but is important in terms of the frequency of involvement of the semilunar valves or atrioventricular valvar attachments, and the likelihood of spontaneous closure. Most infants with VSD present in the neonatal period. However, the clinical presentation varies depending upon the size of the defect and may range from an isolated murmur that is detected incidentally at a health supervision visit to severe heart failure. Signs and symptoms begin to develop when pulmonary vascular resistance (PVR) declines sufficiently to permit left-to-right shunting. Thus, the typical presentation of a small VSD in a neonate involves the detection of a cardiac murmur at four to ten days of life. Other symptoms are usually absent. Mild tachycardia and tachypnea may develop by two to eight weeks of age if the defect is larger than small, particularly with an intercurrent respiratory infection. The normal decline in PVR can be delayed in infants with moderate and large VSDs. Thus, murmurs may not be detected in such infants until several weeks postnatally. Infants with moderate or large VSDs also may present with tachypnea, increased work of breathing, poor weight gain or failure to thrive, and diaphoresis, particularly with feeding. The severity of symptoms depends upon the size of the shunt, and the ability of the left ventricle (LV) to maintain systemic output.
 

Complete Atrio-ventricular Septal Defect: Atrioventricular (AV) canal defects are a group of congenital cardiac defects involving the AV septum and AV valves (ie, mitral and tricuspid valves). They are also referred to as AV septal defects, endocardial cushion defects, or persistent AV ostium. Combinations of these anatomic abnormalities result in complete (both atrial and ventricular septal defects) and partial (only atrial septal defect) forms that are manifested in varying clinical presentations. Atrioventricular (AV) canal defects account for about 4 to 5 percent of congenital heart defects with a reported prevalence of 0.3 to 0.4 per 1000 live births. The male-to-female distribution of AV canal defect is approximately equal, and complete AV canal defects with both atrial and ventricular septal defects occur in half of the cases. There is a strong association between AV canal defects and trisomy 21 (also referred to as Down syndrome), with a 40 to 50 percent risk of Down syndrome in fetuses in whom an AV canal defect is detected. Nonsyndromic AV canal defects appear to be associated with maternal diabetes and obesity.
 

Tetralogy of Fallot:  In 1888, Etienne-Louis Arthur Fallot described three cyanotic patients with four similar anatomic features ● Stenosis of the pulmonary artery● Intraventricular communication● Deviation of the origin of the aorta to the right ● Concentric right ventricular hypertrophy. This constellation of findings has since become known as tetralogy of Fallot (TOF). The clinical presentation of the patient with TOF is dependent upon the degree of right ventricular outflow obstruction: ● Children with severe obstruction and inadequate pulmonary flow typically present in the immediate newborn period with profound cyanosis. ● Children with moderate obstruction and balanced pulmonary and systemic flow may be noticed during elective evaluation for a murmur. These children may also present with hypercyanotic ("tet") spells when RVOT is obstructed during periods of agitation. In addition, some affected newborns will be detected by an evaluation prompted by a failed oximetry screening test. ● Children with minimal obstruction may present with pulmonary overcirculation and heart failure. Most children with this lesion are symptomatic and cyanotic; there is a subgroup, however, with typical morphology and hemodynamics that remains clinically asymptomatic for a period of time (pink variant). In general, the earlier the onset of systemic hypoxemia, the more likely it is that severe pulmonary outflow tract stenosis or atresia is present.
 

Transposition of the Great arteries: Transposition of the great arteries (TGA) is a lesion in which the aorta arises from the right ventricle and the pulmonary artery from the left ventricle. The most common form of TGA is the dextro type (referred to as D-TGA) in which the ventricles are oriented so that the right ventricle is positioned to the right of the left ventricle and the origin of the aorta is anterior and rightward to the origin of the pulmonary artery. The anatomical defect of D-TGA leads to cyanotic heart disease as a result of two parallel circulations. The first sends deoxygenated systemic venous blood to the right atrium and back to the systemic circulation via the right ventricle and aorta, and the second sends oxygenated pulmonary venous blood to the left atrium and back to the lungs via the left ventricle and pulmonary artery. TGA accounts for about 3 percent of all congenital heart disease (CHD) disorders and almost 20 percent of all cyanotic CHD defects.

Total anomalous Pulmonary venous drainage: Total anomalous pulmonary venous connection (TAPVC), also referred to as total pulmonary venous return (TAPVR), is a cyanotic congenital defect in which all four pulmonary veins fail to make their normal connection to the left atrium. This results in drainage of all pulmonary venous return into the systematic venous circulation. The incidence of total anomalous pulmonary venous connection (TAPVC) ranges from 0.6 to 1.2 per 10,000 live births. Among patients born with congenital heart disease (CHD), the incidence of TAPVC ranges between 0.7 and 1.5 percent. It is the fifth most common cause of cyanotic CHD.
 

Hypoplastic Left Heart Syndrome: Hypoplastic left heart syndrome (HLHS) is characterized by a diminutive left ventricle incapable of supporting the systemic circulation. Surgical and medical interventions have improved outcomes of this condition, which untreated is fatal. However, mortality remains high, with a five-year survival rate of about 65 percent even after surgical repair. Hypoplastic left heart syndrome (HLHS) accounts for 2 to 3 percent of all congenital heart disease, with a prevalence rate of two to three cases per 10,000 live births in the United States. HLHS is the most common form of functional single ventricle heart disease. The reported overall incidence is likely underestimated because of the indeterminate rate of spontaneous abortions and elective termination of pregnancy of affected fetuses. Despite its low incidence relative to other congenital cardiac disorders, HLHS, if left untreated, is responsible for 25 to 40 percent of all neonatal cardiac deaths.
 

Vascular Rings: Vascular rings are congenital anomalies of the aortic arch that result in compression of the tracheobronchial tree and/or esophagus, leading to respiratory and gastrointestinal symptoms. They can be classified as either complete, when both the trachea and esophagus are fully encircled by a vascular anomaly, or incomplete without full encirclement of both structures. Aortic arch anomalies are rare malformations accounting for approximately 1 to 3 percent of congenital heart disease. Males have a 1.4 to 2 times greater risk of having a vascular ring than females. Complete vascular rings, which are more commonly associated with significant symptoms, represent the majority of cases.