DiGeorge syndrome is one of the most common microdeletion syndromes, resulting from 22q11 deletion. 10% of the cases can be inherited in an autosomal dominant fashion, while 90% are sporadic. The syndrome is characterized by a deficiency of both T and B-cell lines along with hearing loss, 20-fold increased lifetime chances of developing schizophrenia, renal abnormalities, congenital heart defects, and a borderline or low IQ. Distinctive facial features include micrognathia, long face, short philtrum, cleft palate, and small teeth.

Normal QT interval in a 6 months old baby is < 0.44 seconds. A duration exceeding this value is referred to as QT interval prolongation, which is associated with some important congenital syndromes that include Brugada syndrome which is characterized by vasovagal syncope and sudden cardiac death, Jervell and Lange-Nielsen syndrome which is associated with congenital deafness, Andersen syndrome which is marked by bone deformities, and Timothy syndrome with associated heart disease and immunodeficiency. Romano-Ward syndrome is the commonest cause of congenital QT prolongation with no associated extra-cardiac manifestations. Lown-Ganong-Levine syndrome is characterized by a shortened PR interval and a normal QRS duration.

Infective endocarditis (IE) is defined as an infection of the endocardial surface of the heart.Fever, possibly low-grade and intermittent, is present in 90% of patients with IE. Heart murmurs are heard in approximately 85% of patients.One or more classic signs of IE are found in as many as 50% of patients. They include the following:- Petechiae: Common, but nonspecific, finding- Subungual (splinter) haemorrhages: Dark-red, linear lesions in the nail beds -Osler nodes: Tender subcutaneous nodules usually found on the distal pads of the digits- Janeway lesions: Nontender maculae on the palms and soles- Roth spots: Retinal haemorrhages with small, clear centres| rareSigns of neurologic disease, which occur in as many as 40% of patients, include the following:- Embolic stroke with focal neurologic deficits: The most common neurologic sign- Intracerebral haemorrhage- Multiple microabscessesOther signs of IE include the following:- Splenomegaly- Stiff neck- Delirium- Paralysis, hemiparesis, aphasia- Conjunctival haemorrhage- Pallor- Gallops- Rales- Cardiac arrhythmia- Pericardial rub- Pleural friction rub

Torsade de pointes is an uncommon and distinctive form of polymorphic ventricular tachycardia (VT) characterized by a gradual change in the amplitude and twisting of the QRS complexes around the isoelectric line.Conditions associated with torsade include the following:Electrolyte abnormalities – Hypokalaemia, hypomagnesemia, hypocalcaemiaEndocrine disorders – Hypothyroidism, hyperparathyroidism, pheochromocytoma, hyperaldosteronism, hypoglycaemiaCardiac conditions – Myocardial ischemia, myocardial infarction, myocarditis, bradyarrhythmia, complete atrioventricular (AV) block, takotsubo cardiomyopathyIntracranial disorders – Subarachnoid haemorrhage, thalamic hematoma, cerebrovascular accident, encephalitis, head injuryNutritional disorders – Anorexia nervosa, starvation, liquid protein diets, gastroplasty and ileojejunal bypass, celiac diseaseRisk factors for torsade include the following:Congenital long QT syndromeFemale genderAcquired long QT syndrome (causes of which include medications and electrolyte disorders such as hypokalaemia and hypomagnesemia)BradycardiaBaseline electrocardiographic abnormalitiesRenal or liver failure

Several types of right-sided aortic arch exist, the most common ones being right-sided aortic arch with aberrant left subclavian artery and the mirror-image type. The variant with aberrant left subclavian artery is associated with congenital heart disease in only a small minority of affected people. The mirror-image type of right aortic arch is very strongly associated with congenital heart disease, in most cases tetralogy of Fallot. A right-sided aortic arch does not cause symptoms on itself, and the overwhelming majority of people with the right-sided arch have no other symptoms. However when it is accompanied by other vascular abnormalities, it may form a vascular ring, causing symptoms due to compression of the trachea and/or oesophagus.

The most probable diagnosis for this patient would be Coarctation of Aorta (CoA).Infants with CoA present within the first few weeks of life with signs suggestive of congestive cardiac failure and general circulatory shock. In these patients, the aorta is supplied by the right ventricle, via the ductus arteriosus. Pathophysiology:When the left ventricle supplies the aorta via the aortic isthmus, children are usually asymptomatic or may present with occasional complaints of leg pain. Associated cardiac anomalies are uncommon but for a bicuspid aortic valve, which is present in approximately 50% of cases. Good collateral circulation usually develops in these patients, which in the long term, causes notching of ribs. Clinical Presentation:Clinically, there may be hypertension in the upper limbs (or higher BP readings than in the lower limbs), and leg pulses are absent, or weak and delayed. A systolic click and aortic ejection systolic murmur are heard, caused by the bicuspid aortic valve. Management:The primary medical management is to treat hypertension. After stabilization, the patient can undergo definitive surgical repair. Transcatheter balloon angioplasty of the coarctation is controversial, but ballooning +/- stenting of re-coarctation following surgery is commonly performed.Systemic hypertension may occur following repair, even in the absence of re-coarctation necessitating the re-initiation/continuation of antihypertensive therapy in these patients.

The heart is the first organ to form and become functional, emphasizing the importance of transport of material to and from the developing infant. It originates about day 18 or 19 from the mesoderm and begins beating and pumping blood about day 21 or 22. It forms from the cardiogenic region near the head and is visible as a prominent heart bulge on the surface of the embryo. Originally, it consists of a pair of strands called cardiogenic cords that quickly form a hollow lumen and are referred to as endocardial tubes. These then fuse into a single heart tube and differentiate into the truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and sinus venosus, starting about day 22. The primitive heart begins to form an S shape within the pericardium between days 23 and 28. The internal septa begin to form about day 28, separating the heart into the atria and ventricles, although the foramen ovale persists until shortly after birth. Between weeks five and eight, the atrioventricular valves form. The semilunar valves form between weeks five and nine.

The best answer is Henoch-Schönlein Purpura (HSP). This patient has a characteristic rash and the labs are consistent with this diagnosis.

Hyperkalaemia presents with high voltage (peaked) T waves on ECG. Other features on ECG include smaller p-waves and wider QRS complexes.

The most common congenital cyanotic heart disease and the most common cause of blue baby syndrome, Tetralogy of Fallot shows four cardiac malformations occurring together. These are ventricular septal defect (VSD), pulmonary stenosis (right ventricular outflow obstruction), overriding aorta (degree of which is variable), and right ventricular hypertrophy. The primary determinant of severity of disease is the degree of pulmonary stenosis. Tetralogy of Fallot is seen in 3-6 per 10,000 births and is responsible for 5-7% congenital heart defects, with slightly higher incidence in males. It has also been associated with chromosome 22 deletions and DiGeorge syndrome. It gives rise to right-to-left shunt leading to poor oxygenation of blood. Primary symptom is low oxygen saturation in the blood with or without cyanosis at birth of within first year of life. Affected children ay develop acute severe cyanosis or ‘tet spells’ (sudden, marked increase in cyanosis, with syncope, and may result in hypoxic brain injury and death). Other symptoms include heart murmur, failure to gain weight, poor development, clubbing, dyspnoea on exertion and polycythaemia. Chest X-ray reveals characteristic coeur-en-sabot (boot-shaped) appearance of the heart. Treatment consists of immediate care for cyanotic spells and Blalock–Taussig shunt (BT shunt) followed by corrective surgery.

Congenital heart diseases such as complete atrioventricular septal defects are most likely to cause large left to right shunts leading to faltering growth due to chronic severe hypoxia, pulmonary oedema, and feeding problems. Isolated atrial septal defects or ventricular septal defects result in relatively smaller shunts. Pulmonary stenosis and bicuspid aortic valve do not cause chronic systemic hypoxia. People with these conditions are often asymptomatic and only show some symptoms with intense physical activity.

Coarctation of the aorta is one of the serious forms of congenital heart diseases characterized by a congenitally narrowed down proximal thoracic aorta. This narrowing is usually located distal to the origin of the left subclavian artery. Coarctation can occur in isolation but can accompany other cardiac lesions, including a bicuspid aortic valve. When the coarctation is located just above the left subclavian artery, raised blood pressure can be noted in the right arm. The most common type of murmur found in coarctation of the aorta is a diastolic murmur of aortic regurgitation due to the presence of a bicuspid aortic valve. Exercise augmented cardiac output is only affected in cases where coarctation of the aorta leads to heart failure. Hypertension persists even after the surgical repair and needs to be closely monitored.

Atrial septal defects may also occur in association with a variety of other congenital heart defects, or in new-borns that are relatively small or premature. The following conditions are associated with an atrial septal defect:Ebstein’s anomalyFoetal alcohol syndromeHolt-Oram syndromeDown syndromeEllis van Creveld syndromeLutembacher’s syndrome Ostium primum defects occur frequently in individuals with Down syndrome or Ellis van-Creveld syndrome.Holt-Oram syndrome characterized by an autosomal dominant pattern of inheritance and deformities of the upper limbs (most often, absent or hypoplastic radii) has been attributed to a single gene defect in TBX5Fragile X syndrome is characterized by moderate intellectual disability in affected males and mild intellectual disability in affected females. The physical features in affected males are variable and may not be obvious until puberty. These symptoms can include a large head, long face, prominent forehead and chin, protruding ears, loose joints and large testes. Other symptoms can include flat feet, frequent ear infections, low muscle tone, a long narrow face, high arched palate, dental problems, crossed eyes (strabismus) and heart problems including mitral valve prolapse.

Except Tetralogy of Fallot, the others are acyanotic heart diseases. The cyanotic spells and loss of consciousness are due to spasm of the infundibular septum, which acutely worsens the right ventricular outflow tract obstruction. The given murmur is due to a ventricular septal defect.

A ventricular septal defect (VSD) is a common form of congenital heart defects and is characterised by the presence of a hole in the wall that separates the right from the left ventricle. Medium or large defects can cause many complications. One of these complication is Eisenmenger syndrome, characterised by reversal of the shunt (from left-to-right shunt into a right-to-left) ,cyanosis and pulmonary hypertension.

Auscultatory findings of VSD vary with the size of the defect. Small VSDs typically produce murmurs ranging from a grade 1 to 2/6 high-pitched, short systolic murmur (due to tiny defects that actually close during late systole) to a grade 3 to 4/6 holosystolic murmur (with or without thrill) at the lower left sternal border| this murmur is usually audible within the first few days of life (see table Heart Murmur Intensity). The precordium is not hyperactive, and the 2nd heart sound (S2) is normally split and has normal intensity.Moderate to large VSDs produce a holosystolic murmur that is present by age 2 to 3 wk| S2 is usually narrowly split with an accentuated pulmonary component. An apical diastolic rumble (due to increased flow through the mitral valve) and findings of heart failure (e.g., tachypnoea, dyspnoea with feeding, failure to thrive, gallop, crackles, hepatomegaly) may be present. In moderate, high-flow VSDs, the murmur is often very loud and accompanied by a thrill (grade 4 or 5 murmur). With large defects allowing equalization of left ventricular and right ventricular pressures, the systolic murmur is often attenuated.

Marfan syndrome is a disorder that affects the connective tissue found throughout the body, Marfan syndrome can affect many systems, often causing abnormalities in the heart, blood vessels, eyes, bones, and joints. The two primary features of Marfan syndrome are vision problems caused by a dislocated lens (ectopia lentis) in one or both eyes and aortic root disease, leading to aneurysmal dilatation, aortic regurgitation and dissection is the main cause of morbidity and mortality in Marfan syndrome.

The murmur of tricuspid valve regurgitation is typically a high-pitched, blowing, holosystolic, plateau, nonradiating murmur best heard at the lower left sternal border. The intensity is variable, but tends to increase during inspiration (Carvallo’s sign), with passive leg raising, after a post-extrasystole pause, and following amyl nitrite inhalation. The intensity of the murmur tends to correlate positively with the severity of regurgitation. Right ventricular enlargement may displace the location of the murmur leftward. Right ventricular failure may abolish respiratory variation. When tricuspid regurgitation is caused by pulmonary hypertension, a pulmonic ejection click may be audible. Severe tricuspid regurgitation is commonly accompanied by a third heart sound emanating from the right ventricle and best heard at the lower left sternal border. Severe tricuspid regurgitation typically produces an accentuated jugular cv wave and may produce hepatic congestion with a pulsatile liver.The auscultatory findings associated with ventricular septal defect are variable, depending on a variety of morphologic and hemodynamic considerations. The systolic murmur associated with a Roger’s-type ventricular septal defect (regurgitant jet flows directly into the right ventricular outflow tract) in patients with low pulmonary vascular resistance is a low to medium pitched, holosystolic murmur with midsystolic accentuation. The intensity of the murmur is typically grade 3 or higher.Patent ductus arteriosus produces a continuous murmur in patients with normal pulmonary vascular resistance.

Although WPW syndrome is a type of supraventricular re-entrant tachycardia, CCBs are contraindicated in its management. This is because CCBs depress AVN conduction| the current then passes through the accessory pathway (bundle of Kent) instead, causing ventricular tachycardia.

The most common congenital cyanotic heart disease and the most common cause of blue baby syndrome, Tetralogy of Fallot shows four cardiac malformations occurring together. These are ventricular septal defect (VSD), pulmonary stenosis (right ventricular outflow obstruction), overriding aorta (degree of which is variable), and right ventricular hypertrophy. The primary determinant of severity of disease is the degree of pulmonary stenosis. Tetralogy of Fallot is seen in 3-6 per 10,000 births and is responsible for 5-7% congenital heart defects, with slightly higher incidence in males. It has also been associated with chromosome 22 deletions and DiGeorge syndrome. It gives rise to right-to-left shunt leading to poor oxygenation of blood. Primary symptom is low oxygen saturation in the blood with or without cyanosis at birth of within first year of life. Affected children ay develop acute severe cyanosis or ‘tet spells’ (sudden, marked increase in cyanosis, with syncope, and may result in hypoxic brain injury and death). Other symptoms include heart murmur, failure to gain weight, poor development, clubbing, dyspnoea on exertion and polycythaemia. Chest X-ray reveals characteristic coeur-en-sabot (boot-shaped) appearance of the heart. Treatment consists of immediate care for cyanotic spells and Blalock–Taussig shunt (BT shunt) followed by corrective surgery.

Cyanotic congenital heart disease (CCHD) is a common cause of neonatal morbidity and mortality. They can be classified as CCHD due to:- Right-to-left shunt, associated with the decreased pulmonary flow, e.g., tetralogy of Fallot (TOF), pulmonary atresia, right-sided hypoplastic heart,- Right-to-left shunt, associated with the decreased aortic flow, e.g., left-sided hypoplastic heart, interrupted arch, severe coarctation| – Bidirectional shunt, e.g., TGA, DORV, TA, etc. Eisenmenger syndrome is not a neonatal CCHD| rather it develops later in young adulthood secondary to various CHD.

The most probable diagnosis in this patient would be pulmonary stenosis. Pulmonary Stenosis:Pulmonary valve murmurs are heard in the upper left sternal edge, associated with a thrill but no desaturation in the absence of an additional shunt. The ECG changes suggest right ventricular hypertrophy. Pulmonary stenosis is often well tolerated in childhood unless severe. These should be monitored with serial echocardiography, and balloon pulmonary valvoplasty should be considered once the pressure gradient reaches 64 mmHg.Other options:- Atrial septal defect: While atrial septal defects are associated with right ventricular outflow tract murmurs, they would not cause a thrill.- Patent ductus arteriosus: PDA murmurs can be audible in the left upper sternal edge, but would normally be audible in the left infraclavicular area and be continuous rather than ejection systolic. This left to right shunt would not cause desaturation but does cause left-sided volume loading and hence left-sided ECG changes.- Tetralogy of Fallot: Ventricular septal defect, overriding aorta, subpulmonary stenosis, and right ventricular hypertrophy. This would often cause a ULSE murmur with a thrill and RVH on ECG. However, this degree of obstruction would cause shunting from right to left, and this child would be desaturated.- Ventricular septal defect: Isolated ventricular septal defects cause pansystolic murmurs at the left lower sternal edge. They would have left-sided ECG changes and normal saturations (in the absence of pulmonary hypertension).

Infective endocarditis (IE) is an acute infective pathology of the endocardium secondary to some underlying cardiac pathology like VSD and TOF. Most commonly, it is bacterial in origin, caused by staphylococcus aureus in the majority of cases. Clinical features include fever, arthralgias, weight loss, anorexia, new-onset, or changing existing murmur. Skin manifestations include Osler’s nodes, Janeway lesions, splinter haemorrhages, and clubbing. Roth spots are conjunctival haemorrhages found in IE. Beau’s lines are not found in IE.

Tetralogy of Fallot (TOF), a congenital heart defect, includes the following: right ventricular hypertrophy, ventricular septal defect, abnormal position of the aorta and pulmonary valve stenosis. The O2 saturation in patients with TOF is typically lower than normal and the condition usually becomes symptomatic early in life. A feature of the disease with high diagnostic significance is squatting or crouching of the infant as a compensatory mechanism to increase the peripheral vascular resistance.

Tricuspid atresia is the third most common form of cyanotic congenital heart disease, with a prevalence of 0.3-3.7% in patients with congenital heart disease. The deformity consists of a complete lack of formation of the tricuspid valve with the absence of a direct connection between the right atrium and right ventricle.The following 3 considerations guide the treatment of infants with tricuspid atresia:- The amount of pulmonary blood flow must be regulated to decrease hypoxemia or symptoms of congestive heart failure.- Myocardial function, the integrity of the pulmonary vascular bed, and pulmonary vascular integrity must be preserved to optimize conditions for a later Fontan operation.- The risk of bacterial endocarditis and thromboembolism must be minimized.Infants with decreased pulmonary blood flow: encompasses most of the infants with tricuspid atresia.Marked cyanosis and hypoxemia characterize the clinical course. Acidaemia may occur if the hypoxemia is profound, and death can ensue.Promptly treat infants with severe hypoxemia with prostaglandin E infusions to maintain patency of the ductus arteriosus and improve pulmonary blood flow.Infants with increased pulmonary blood flow: These infants have an associated unrestrictive ventricular septal defect and transposed great vessels.They present with severe congestive heart failure and benefit from digitalis and diuretic therapy until an operative intervention can be undertaken to restrict the pulmonary blood flow.

Key observations in the results:

1. Oxygen Saturation Step-Up:
   • There is a significant step-up in oxygen saturation from the right ventricle (72%) to the pulmonary artery (86%). This suggests the presence of left-to-right shunting of blood.
2. Pressure Differences:
   • The pressure in the pulmonary artery is elevated (53/13 mmHg), indicating pulmonary hypertension.

Differential Diagnosis:

1. Patent Ductus Arteriosus (PDA):
   • PDA can cause increased pulmonary blood flow, leading to a step-up in oxygen saturation in the pulmonary artery. The pulmonary artery pressures can also be elevated due to increased blood flow.
2. Primary Pulmonary Hypertension:
   • Typically presents with elevated pulmonary pressures but does not usually show a step-up in oxygen saturation.
3. Pulmonary Stenosis:
   • Would result in elevated right ventricular pressure but would not explain the step-up in oxygen saturation.
4. Septum Primum Atrial Septal Defect (ASD):
   • Would result in a step-up in oxygen saturation from the right atrium to the right ventricle, not between the right ventricle and pulmonary artery.
5. Tetralogy of Fallot:
   • Characterized by right ventricular outflow tract obstruction, VSD, right ventricular hypertrophy, and an overriding aorta. Oxygen saturation levels would typically be lower in the systemic circulation.

Coarctation of the aorta is one of the serious forms of congenital heart diseases Occurring in about 1 in 2,500 births. It is characterized by a congenitally narrowed proximal thoracic aorta. Coarctation can occur in isolation but can accompany other cardiac lesions, including a bicuspid aortic valve in 70% of the cases and berry aneurysms in 10% of the cases. Coarctation of the aorta is commonly found in association with Turner’s syndrome, Edward’s syndrome, and Patau syndrome.

Key Observations:

1. Cyanosis and Low Oxygen Saturation:
   • Central cyanosis indicates mixing of oxygenated and deoxygenated blood.
   • The aortic oxygen saturation is low (76%), indicating a significant amount of deoxygenated blood entering systemic circulation.
2. Pressure Analysis:
   • The right ventricle pressure is significantly elevated (110/6 mmHg), suggesting an obstructive lesion like pulmonary stenosis or an increased volume load due to a shunt.
   • The pulmonary artery pressure is low (20/5 mmHg) despite the high right ventricular pressure, suggesting an obstruction to flow from the right ventricle to the pulmonary artery, consistent with pulmonary stenosis.
3. Oxygen Saturation Analysis:
   • There is a notable drop in oxygen saturation from the left ventricle (87%) to the aorta (76%), indicating a mixture of oxygenated and deoxygenated blood in the systemic circulation, suggestive of a right-to-left shunt.

Differential Diagnosis:

1. Pulmonary Stenosis:
   • Supported by elevated right ventricular pressure and low pulmonary artery pressure.
2. Ventricular Septal Defect (VSD):
   • Would typically cause left-to-right shunting, leading to increased pulmonary blood flow and higher oxygen saturation in the right ventricle and pulmonary artery, which is not observed here.
3. Over-riding Aorta:
   • Seen in conditions like Tetralogy of Fallot where the aorta receives blood from both the right and left ventricles, leading to mixed oxygen saturation.
4. Right-to-Left Shunt:
   • The data indicates a right-to-left shunt, with low oxygen saturation in the aorta, suggesting that deoxygenated blood is bypassing the lungs and entering systemic circulation.
5. Aortic Stenosis:
   • Typically presents with high left ventricular pressure and a pressure gradient between the left ventricle and the aorta, which is not observed here.

Conclusion:

Given the data, the most likely abnormalities present in this patient are Pulmonary Stenosis, Right-to-Left Shunt, and Over-riding Aorta. These findings are consistent with a condition like Tetralogy of Fallot, where all these features are present.

Coarctation of the aorta may be defined as a constricted aortic segment that comprises localized medial thickening, with some infolding of the medial and superimposed neointimal tissue.The presence of associated defects and aortic arch anomalies, the extent of patency of the ductus arteriosus, the rapidity of the process of closure of the ductus arteriosus, and the level of pulmonary vascular resistance determine the timing of clinical presentation and the severity of symptoms. Young patients may present in the first few weeks of life with poor feeding, tachypnoea, and lethargy and progress to overt CHF and shock. These patients may have appeared well before hospital discharge, and deterioration coincides with closure of the patent ductus arteriosus. Presentation may be abrupt and acute with ductal closure.Neonates may be found to have tachypnoea, tachycardia, and increased work of breathing and may even be moribund with shock. Keys to the diagnosis include blood pressure (BP) discrepancies between the upper and lower extremities and reduced or absent lower extremity pulses to palpation. However, when the infant is in severe heart failure, all pulses are diminished.The murmur associated with coarctation of the aorta may be nonspecific yet is usually a systolic murmur in the left infraclavicular area and under the left scapula.

The most possible diagnosis is SVT. The boy is suffering from hemodynamic instability, as indicated by his cold extremities. DC cardioversion is the treatment of choice.