Congenital Heart Defects

| At what point in gestation does the heart become a 4-chambered structure with absorption of pulmonary veins?

| By 7 weeks (49 days). | Embryology | 1 |

| What is the general classification of Congenital Heart Defects?

| They are broadly classified into Acyanotic and Cyanotic defects. | Classification | 2 |

| How are Acyanotic Congenital Heart Defects further subdivided?

| Into lesions causing volume load (left-to-right shunts) and lesions causing pressure load (obstructive ventricular outflow). | Classification | 3 |

| List two examples of acyanotic CHD with volume load (left-to-right shunts).

| Atrial septal defect, ventricular septal defect, AV canal, or patent ductus arteriosus. (Any 2) | Classification | 4 |

| List two examples of acyanotic CHD with pressure load (obstructive outflow).

| Pulmonary valve stenosis, aortic valve stenosis, or coarctation of aorta. (Any 2) | Classification | 5 |

| How are Cyanotic Congenital Heart Defects further subdivided?

| Into lesions with increased pulmonary flow and lesions with decreased pulmonary flow. | Classification | 6 |

| List two examples of cyanotic CHD with increased pulmonary flow.

| Transposition of great vessels, single ventricle, truncus arteriosus, or total anomalous pulmonary return without obstruction. (Any 2) | Classification | 7 |

| List two examples of cyanotic CHD with decreased pulmonary flow.

| Tetralogy of Fallot, pulmonary atresia, tricuspid atresia, or total anomalous pulmonary return with obstruction. (Any 2) | Classification | 8 |

| What is the basic pathophysiology of a left-to-right shunt?

| Oxygenated blood recirculates in the lungs. | Pathophysiology | 9 |

| What is the basic pathophysiology of a right-to-left shunt?

| Desaturated blood bypasses the lungs. | Pathophysiology | 10 |

| What is the basic pathophysiology of a transposition lesion?

| The systemic and pulmonary circulations run in parallel. | Pathophysiology | 11 |

| What is the basic pathophysiology of an obstructive lesion in CHD?

| There is an increased workload on the affected cardiac chamber. | Pathophysiology | 12 |

| What are the key components of diagnosing congenital heart disease?

| History, examination, and investigations (radiological and laboratory). | Diagnosis | 13 |

| What is an Atrial Septal Defect (ASD)?

| A failure of complete closure of the interatrial septum. | ASD | 14 |

| What is the basic physiology of an Atrial Septal Defect (ASD)?

| A left-to-right shunt at the atrial level. | ASD | 15 |

| What factors determine the magnitude of the shunt in an ASD?

| The size of the defect and the compliance of the Right Ventricle (RV). | ASD | 16 |

| What are the hemodynamic consequences of an ASD?

| Volume overload of the Right Atrium (RA), Right Ventricle (RV), and Pulmonary Artery (PA). May also lead to Tricuspid Regurgitation (TR) and Pulmonary Regurgitation (PR). | ASD | 17 |

| What are the potential complications of a moderate to large ASD?

| RA and RV enlargement, arrhythmia (atrial fibrillation), heart failure, pulmonary hypertension, and paradoxical emboli. | ASD | 18 |

| What is the most characteristic auscultatory finding in an ASD?

| A fixed, widely split S2. | ASD | 19 |

| Describe the murmur associated with an ASD.

| A systolic ejection murmur at the Left Upper Sternal Border (LUSB) that radiates to the lung fields, and a soft diastolic murmur at the Left Lower Sternal Border (LLSB). | ASD | 20 |

| What are the treatment options for an Atrial Septal Defect (ASD)?

| Surgical closure or closure by device in the catheterization lab. | ASD | 21 |

| What primarily determines the physiology of a Ventricular Septal Defect (VSD)?

| The size of the VSD. | VSD | 22 |

| Differentiate between a "restrictive" and "non-restrictive" VSD.

| Small to medium size defects are "restrictive" (pressure limiting). Large defects are "non-restrictive" and provide no resistance to flow between ventricles. | VSD | 23 |

| In a large VSD, what determines the flow across the defect?

| The relative resistance in the pulmonary and systemic vascular beds. | VSD | 24 |

| What is the consequence of low pulmonary vascular resistance (PVR) in a large VSD versus high PVR?

| If PVR is low, there is a lot of flow and a lot of symptoms. If PVR is high, there is less flow and the patient may be asymptomatic. | VSD | 25 |

| How does a child with a significant VSD typically present, and at what age?

| With congestive heart failure at 2-3 weeks of age. | VSD | 26 |

| What are the symptoms of congestive heart failure in an infant with a VSD?

| Sweating during feeds, difficulty in feeding, inadequate weight gain, and recurrent chest infections. | VSD | 27 |

| What are the signs of congestive heart failure in an infant with a VSD?

| Tachypnea, tachycardia, mottled skin, cold periphery, and possibly an enlarged liver. | VSD | 28 |

| What are the potential courses/complications of a VSD?

| LA/LV enlargement, CHF, pulmonary hypertension, development of RV outflow obstruction, aortic insufficiency, endocarditis, or spontaneous closure. | VSD | 29 |

| What is the initial management for symptomatic VSDs?

| Medical management first, focusing on heart failure (diuretics, ACE inhibitors), nutrition, and good oral hygiene. Some small defects may close spontaneously. | VSD | 30 |

| What are the indications for intervention (surgery/catheterization) for a VSD?

| Failure of medical management, aortic insufficiency, Qp/Qs > 2:1 in older children, or pulmonary hypertension (repair before 1 year of age). | VSD | 31 |

| What is an Atrioventricular Septal Defect (AVSD) or AV Canal Defect, and with which genetic condition is it strongly associated?

| A defect involving both the atrial and ventricular septa with a common AV valve. It is strongly associated with Trisomy 21. | AVSD | 32 |

| What factors determine the magnitude of the shunt in a Patent Ductus Arteriosus (PDA)?

| 1. The pressure gradient between the aorta (Ao) and pulmonary artery (PA). 2. The resistance within the PDA itself. | PDA | 33 |

| What are the pathophysiological effects of a significant PDA?

| Pulmonary over-circulation, decreased lung compliance (increased work of breathing), increased pulmonary venous return to the LA, left heart enlargement, and diastolic run-off in the aorta with low diastolic BP. | PDA | 34 |

| Describe the classic murmur of a Patent Ductus Arteriosus (PDA).

| A continuous, "machinery" murmur, best heard in the left infraclavicular region, with no change with position. | PDA | 35 |

| What are the clinical signs of a significant PDA?

| Heart failure and bounding pulses with a wide pulse pressure. | PDA | 36 |

| What are the treatment options for a Patent Ductus Arteriosus (PDA)?

| Medical (Ibuprofen in neonates, heart failure management), catheterization (device closure), or surgical ligation. | PDA | 37 |

| What is a ductal dependent lesion in congenital heart disease?

| A congenital heart defect where patency of the ductus arteriosus is essential for survival, either for pulmonary blood flow, systemic blood flow, or for mixing of the two circulations. | Ductal Dependent Lesions | 38 |

| Name two conditions that require a PDA for pulmonary blood flow (right heart obstruction).

| Critical Pulmonary Stenosis (PS), Tetralogy of Fallot (ToF), Pulmonary Atresia (PA), or Tricuspid Atresia (TA). (Any 2) | Ductal Dependent Lesions | 39 |

| Name two conditions that require a PDA for systemic blood flow (left heart obstruction).

| Critical Aortic Stenosis (AS), Coarctation of the Aorta (CoArc), Hypoplastic Left Heart Syndrome (HLHS), or Interrupted Aortic Arch (IAA). (Any 2) | Ductal Dependent Lesions | 40 |

| Which condition requires a PDA for mixing of the parallel systemic and pulmonary circulations?

| d-Transposition of the Great Arteries (dTGA). | Ductal Dependent Lesions | 41 |

| What is Coarctation of the Aorta?

| A congenital narrowing of the aorta, most typically at the isthmus. | Coarctation | 42 |

| What is the prevalence of Coarctation of the Aorta, and with what genetic syndrome is it associated?

| 6-8% of all CHD, more common in males. Occurs in 12-35% of patients with Turner's Syndrome. | Coarctation | 43 |

| What other cardiac anomaly is associated with 85% of Coarctation of the Aorta cases?

| Bicuspid Aortic Valve. | Coarctation | 44 |

| How does critical Coarctation of the Aorta present in a newborn?

| Presents within the first 2 weeks of life with signs of congestive heart failure, acidosis, and shock upon ductal closure. Signs include dyspnea, poor feeding, poor pulses, and saturation differences. | Coarctation | 45 |

| What is the immediate treatment for a newborn with critical Coarctation of the Aorta?

| Start Prostaglandin E1 (PGE1) infusion to reopen the ductus arteriosus, stabilize the infant, and then proceed to surgery. | Coarctation | 46 |

| What are the key physical findings in an older child or adult with Coarctation of the Aorta?

| Decreased and delayed pulses in the lower extremities, and a systolic blood pressure difference between the upper and lower limbs. | Coarctation | 47 |

| What are the three main levels of obstruction in valve stenosis, and which is most common?

| Obstruction can be at the valve (90%, most common), subvalve, or supravalve level. | Valve Stenosis | 48 |

| How does Pulmonary Valve Stenosis typically present, and how is it treated?

| Presents with a murmur and signs of Right Ventricular Hypertrophy (RVH). Treatment is in the cath lab with Balloon Pulmonary Valvuloplasty (BPV). | Valve Stenosis | 49 |

| What are the common etiologies of Aortic Stenosis?

| Can be congenital, associated with a Bicuspid Aortic Valve, or due to other causes. | Valve Stenosis | 50 |

| What are the three main causes of central cyanosis?

| Right-to-left shunting in the heart, right-to-left shunting in the lungs, or methemoglobinemia. | Cyanotic CHD | 51 |

| Name three common cyanotic congenital heart diseases.

| Tetralogy of Fallot (ToF), Transposition of Great Arteries (TGA), Tricuspid atresia, Truncus Arteriosus, or Total Anomalous Pulmonary Venous Return (TAPVR). (Any 3) | Cyanotic CHD | 52 |

| What are the four components of Tetralogy of Fallot (ToF)?

| 1. A large, unrestrictive VSD (malalignment type). 2. An overriding aorta. 3. Pulmonary stenosis (infundibular, valvular, or hypoplasia of PAs). 4. Right Ventricular Hypertrophy (RVH). | Tetralogy of Fallot | 53 |

| What is the key anatomical feature of Tetralogy of Fallot?

| Anterior deviation of the infundibular septum. | Tetralogy of Fallot | 54 |

| What determines the direction and magnitude of the shunt in Tetralogy of Fallot?

| The severity of the Right Ventricular Outflow Tract (RVOT) obstruction. | Tetralogy of Fallot | 55 |

| What are "Tet Spells" or hypercyanotic spells in Tetralogy of Fallot?

| Acute episodes of intense cyanosis with hyperpnea due to spasm of the infundibulum, leading to decreased pulmonary blood flow, severe hypoxemia, and high mortality. | Tetralogy of Fallot | 56 |

| What is the characteristic appearance of the heart on a chest X-ray in Tetralogy of Fallot?

| A "boot-shaped" heart with an upturned apex and concave Left Upper Sternal Border. Heart size is small or normal, and pulmonary vascular markings are normal or decreased. A right aortic arch is seen in 25% of cases. | Tetralogy of Fallot | 57 |

| What is the immediate management for a hypercyanotic "Tet Spell"?

| 1. Avoid agitation. 2. Place the child in a knee-chest position. 3. Administer oxygen. 4. Give an IV fluid bolus (saline). 5. Sedation (morphine/ketamine). 6. Beta-blocker (propranolol). 7. Phenylephrine. 8. ICU care. | Tetralogy of Fallot | 58 |

| What is d-Transposition of the Great Arteries (TGA)?

| A condition of atrio-ventricular concordance with ventriculo-arterial discordance, meaning the pulmonary artery arises from the left ventricle and the aorta arises from the right ventricle. | TGA | 59 |

| How does a newborn with simple TGA typically present?

| Presents at birth with severe cyanosis. | TGA | 60 |

| What is the immediate stabilization for a newborn with TGA?

| 1. Start a Prostaglandin E1 (PGE1) infusion to keep the ductus arteriosus open for mixing. 2. Perform a Balloon Atrial Septostomy (Rashkind procedure) to create an ASD for mixing. | TGA | 61 |

| What is Truncus Arteriosus?

| A condition where a single arterial trunk supplies both the pulmonary and systemic circulations, accompanied by a ventricular septal defect, resulting in a left-to-right shunt. | Truncus Arteriosus | 62 |

| Name two examples of univentricular hearts or "single ventricles".

| Tricuspid Atresia or Hypoplastic Left Heart Syndrome. | Single Ventricle | 63 |

| What is Total Anomalous Pulmonary Venous Connections (TAPVC) or Return (TAPVR)?

| A condition where all four pulmonary veins fail to connect to the left atrium and instead drain anomalously into the systemic venous circulation. | TAPVC | 64 |