Podcast
Questions and Answers
What is the primary issue in total anomalous pulmonary venous return (TAPVR)?
What is the primary issue in total anomalous pulmonary venous return (TAPVR)?
Which type of TAPVR involves drainage of the common pulmonary vein into the superior vena cava?
Which type of TAPVR involves drainage of the common pulmonary vein into the superior vena cava?
What postoperative strategy is recommended for managing pulmonary vein obstruction in TAPVR?
What postoperative strategy is recommended for managing pulmonary vein obstruction in TAPVR?
Which of the following is NOT characteristic of Tetralogy of Fallot (TOF)?
Which of the following is NOT characteristic of Tetralogy of Fallot (TOF)?
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What is the most common cyanotic congenital heart abnormality?
What is the most common cyanotic congenital heart abnormality?
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What imaging finding is typically seen with TAPVR?
What imaging finding is typically seen with TAPVR?
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What type of TAPVR leads to drainage into the coronary sinus?
What type of TAPVR leads to drainage into the coronary sinus?
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Which anatomical component is NOT part of Tetralogy of Fallot?
Which anatomical component is NOT part of Tetralogy of Fallot?
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What is the primary issue faced by infants with unrepaired Tetralogy of Fallot during hypercyanotic episodes?
What is the primary issue faced by infants with unrepaired Tetralogy of Fallot during hypercyanotic episodes?
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Which of the following symptoms is NOT characteristic of hypercyanotic episodes in Tetralogy of Fallot?
Which of the following symptoms is NOT characteristic of hypercyanotic episodes in Tetralogy of Fallot?
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What is the primary consequence of the heart defect known as Truncus Arteriosus?
What is the primary consequence of the heart defect known as Truncus Arteriosus?
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What condition can infants with Truncus Arteriosus develop due to impaired blood flow?
What condition can infants with Truncus Arteriosus develop due to impaired blood flow?
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In Transposition of the Great Arteries, which artery arises from the right ventricle?
In Transposition of the Great Arteries, which artery arises from the right ventricle?
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What surgical procedure is commonly performed to correct Transposition of the Great Arteries?
What surgical procedure is commonly performed to correct Transposition of the Great Arteries?
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Why is early intervention critical for infants with Truncus Arteriosus?
Why is early intervention critical for infants with Truncus Arteriosus?
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What is the primary clinical manifestation of aortic stenosis if dependent on PDA flow?
What is the primary clinical manifestation of aortic stenosis if dependent on PDA flow?
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Which of the following treatments is NOT typically used for acute hypercyanotic episodes in Tetralogy of Fallot?
Which of the following treatments is NOT typically used for acute hypercyanotic episodes in Tetralogy of Fallot?
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Which emergency therapy is recommended for aortic stenosis?
Which emergency therapy is recommended for aortic stenosis?
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What is one of the main pathophysiological effects of coarctation of the aorta?
What is one of the main pathophysiological effects of coarctation of the aorta?
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Which of the following is NOT a treatment option for aortic stenosis?
Which of the following is NOT a treatment option for aortic stenosis?
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What condition is characterized by a severe narrowing of the thoracic aorta?
What condition is characterized by a severe narrowing of the thoracic aorta?
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Which of the following congenital heart lesions is classified as cyanotic?
Which of the following congenital heart lesions is classified as cyanotic?
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What is a common clinical manifestation of coarctation of the aorta?
What is a common clinical manifestation of coarctation of the aorta?
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What risk is associated with aortic stenosis?
What risk is associated with aortic stenosis?
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Study Notes
Congenital Cardiac Defects
- Congenital cardiac defects are the most common birth defect in the United States
- Major developments in identification and surgical techniques have led to a decrease in mortality rates in the last few decades
- Many children with congenital heart disease survive into adulthood
- Prevalence of some common congenital heart defects (ventricular septal defect, atrial septal defect, other non-cyanotic CHD, cyanotic CHD, unspecified CHD) is shown, broken down by males and females, and percentages of each within the total CHD population.
Learning Objectives
- Describe normal cardiac anatomy and blood flow in newborns
- Describe the normal transition from intrauterine to extrauterine blood flow
- Define shunt and different types of shunts in congenital heart disease
- Understand the basic classification schemes for congenital cardiac defects
- Explain the most common congenital cardiac defects
- Recognize causes of changes in pulmonary vascular resistance
- Describe the importance of balancing pulmonary and systemic blood flow (Qp/Qs) associated with various defects
- Recommend ventilator strategies and limitations of various physiological monitoring methods for patients with congenital cardiac defects
Key Terms
- Atrioventricular septal defect
- Coarctation of the aorta
- Fontan procedure
- Glenn procedure
- Hypoplastic left heart syndrome
- Left-to-right shunt
- Norwood procedure
- Patent ductus arteriosus
- Right-to-left shunt
- Tetralogy of Fallot
- Transposition of the great arteries
- Truncus arteriosus
Incidence
- Congenital heart defects are among the most common birth defects in the United States
- Major improvements including surgical techniques and improved postoperative care resulted in significant improvements in mortality over the twentieth century
- Since then mortality rates have been decreasing by decades
Cardiopulmonary Anatomy and Physiology (Part 1 of 3)
- A normal human heart consists of two atria and two ventricles
- Each ventricle has an outflow which contains a valve
- The cardiac cycle consists of myocardial contraction (systole) and myocardial relaxation (diastole).
Cardiopulmonary Anatomy and Physiology (Part 2 of 3)
- Deoxygenated blood enters the right atrium (RA), goes to the right ventricle (RV) via the tricuspid valve, and then into the pulmonary arteries
- Oxygen diffuses into plasma and red blood cells, and carbon dioxide diffuses from plasma into the alveolus
- Oxygenated blood returns to the heart via the pulmonary veins to the left atrium (LA), left ventricle (LV), aortic valve, and into systemic circulation.
Cardiopulmonary Anatomy and Physiology (Part 3 of 3)
- The structure of each cardiac chamber is tailored to its function
- The walls of the atria are thin and compliant to enable expansion during variable systemic and pulmonary venous return
- The right ventricle (RV) is thin-walled, operates under low pressure, and cannot tolerate large increases in afterload
- The muscular, concentric left ventricle (LV) operates at higher systemic pressure.
Transition of Fetal to Extrauterine Life (Part 1 of 3)
- During fetal development, gas exchange occurs via the placenta
- Fetal heart has shunts that bypass the pulmonary circulation
- In utero, the lungs are fluid filled, and pulmonary blood flow (PBF) is limited due to high resistance
Transition of Fetal to Extrauterine Life (Part 2 of 3)
- Patent ductus arteriosus (PDA) connects the pulmonary artery (PA) to the systemic circulation, shunting blood from PA to descending aorta
- Patent foramen ovale (PFO) facilitates flow from the right atrium (RA) to the left atrium (LA)
Transition of Fetal to Extrauterine Life (Part 3 of 3)
- Immediately after birth, physiologic changes occur during the first breath
- The neonate generates pressures in excess of 80 mmHg
- Air replaces fluid in the lungs
- Increased PaO2 and reduced PVR (pulmonary vascular resistance)
- Increased left atrial pressure leads to foramen ovale closure
Cardiopulmonary Interactions
- Preload describes the ventricular end-diastolic volume, describing how full the heart is
- Afterload refers to the downstream pressure the heart pumps against
- Afterload is related to myocardial oxygen demand
Respiratory Cycle (Part 1 of 2)
- Inspiration is an active process in spontaneously breathing patients
- Respiratory and intercostal muscles contract, expanding the chest wall
- Intrapulmonary pressures become negative (subatmospheric) during inspiration
- Pressure gradient drives flow into the lungs
Respiratory Cycle (Part 2 of 2)
- Expiration is a passive process in which passive chest wall relaxation leads to positive intrapulmonary pressures
- Air is expelled from the lungs
The Right Heart
- The venous system operates at low pressure
- Intrathoracic pressures during the respiratory cycle can affect venous return and blood volume received by the right side of the heart
- Low pressure gradient causes flow from systemic veins to the RA
The Left Heart
- Preload to the left heart is dynamic throughout the respiratory cycle
- Inspiration significantly increases pulmonary arteriolar capacitance
- Afterload of the left ventricle is predominantly determined by impedance to systemic blood flow
- Acute changes in LV afterload can occur during PPV (positive pressure ventilation)
Classification of Cardiac Anomalies
- Acyanotic heart diseases exhibit normal systemic oxygenation and left-to-right shunting. Left-to-right shunting can cause muscularization of the pulmonary arteries leading to increased PVR
- Cyanotic heart diseases exhibit decreased systemic oxygenation and a right-to-left shunt
Acyanotic Lesions
- May exhibit a shunt (left-to-right)
- Valvar abnormalities
- Common shunt lesions include: Patent ductus arteriosus (PDA), atrial septal defects (ASD), ventricular septal defects (VSD), and complete atrioventricular canal (CAVC) defects
Patent Ductus Arteriosus (PDA) (Part 1/2)
- PDA is present 48 hours after birth
- Decrease in prostaglandin E2 and increase in PaO2 = closure
- Prematurity is the most common predisposing factor
- Persistent pulmonary hypertension, respiratory distress syndrome (RDS) lead to increased PVR
Patent Ductus Arteriosus (PDA) (Part 2/2)
- Clinical signs include tachypnea, tachycardia, and a continuous murmur
- Post-ductal desaturation and increased pulmonary blood flow may delay wean from respiratory support
- Management options include Indomethacin and Surgical closure
Atrial Septal Defect (ASD)
- Communication between the right and left atria exhibits left-to-right shunting
- Blood flow is determined by the relative compliance of the two ventricles with the thicker-walled left ventricle (LV) having a higher systolic pressure
- Less than 10% ASD children exhibit symptoms before 2 years old, and spontaneous closure may occur within first year of life.
- Surgical repair is a solution
Ventricular Septal Defect (VSD) (Part 1/3)
- VSDs are a communication between the right and left ventricles
- This is often one of the most common congenital heart defects
- Described as perimembranous, subpulmonary, muscular, or inlet, potentially singular or multiple.
Ventricular Septal Defect (VSD) (Part 2/3)
- VSD pathophysiology depends on the size of the defect
- Small defects may close spontaneously and remain asymptomatic
- Larger, unrestrictive VSDs create left-to-right shunting, increased pulmonary artery hypertension, and develop Eisenmenger's syndrome.
Ventricular Septal Defect (VSD) (Part 3/3)
- Therapy for unrestrictive VSDs with heart failure involves surgical closure
- Mild VSDs can be treated with diuretics and digoxin
- Percutaneous transcatheter closure for selected VSD cases.
- Early extubation can sometimes be expected post VSD surgery.
Complete Atrioventricular Canal (CAVC) (Part 1/3)
- Complete atrioventricular canal is an atrioventricular septal defect (AVSD)
- It always involves a common (singular) AV valve
- Often involves abnormalities in the lower portion of the atrial septum
- Most common in infants with Down syndrome (trisomy 21)
Complete Atrioventricular Canal (CAVC) (Part 2/3)
- Partial AVSD is characterized by a primum ASD and common AV valve, without ventricular septal defects
- Complete AVSD is characterized by the absence of parts of the atrial and ventricular septum and a common atrioventricular valve
Complete Atrioventricular Canal (CAVC) (Part 3/3)
- Treatment approaches may include supplemental oxygen, diuretics and digoxin, and surgical repair, including palliation with pulmonary artery banding to stabilize growth
- Surgical repair may involve single or double patch and modified single patch procedures
Valvar Anomalies (Part 1/2)
- Valvar abnormalities involve outflow tracts (semilunar valves: pulmonary and aortic) and atrioventricular valves (mitral or tricuspid valves)
- These lead to regurgitation or stenosis
Valvar Anomalies (Part 2/2)
- Obstructions can be complete (atresia) with no flow or partial (stenotic) with partial flow
Left Ventricular Outflow Tract (LVOT) Obstruction
- Left ventricular outflow tract (LVOT) obstruction exists along a spectrum with impaired left side heart flow in utero.
- Without blood flow, growth is poor and aortic stenosis, or coarctation of the aorta may result.
Aortic Stenosis (AS) (Part 1/2)
- Aortic stenosis (AS) is a narrowing of the aortic valve orifice.
- Clinical presentation is determined by the degree of stenosis. Survival of some infants is dependent on PDA (patent ductus arteriosus) flow
- Metabolic acidosis, poor perfusion, and pulmonary edema may result
Aortic Stenosis (AS) (Part 2/2)
- Emergency therapy may involve opening the PDA for systemic flow and aortic balloon valvotomy to minimize oxygen demand
- Surgical repair includes valvuloplasty, artificial aortic valve replacement, and Ross procedure (pulmonary autograft replacement).
- Hypertension management during and post-surgery is crucial.
Coarctation of the Aorta
- A severe narrowing of the thoracic aorta at the insertion site of the ductus arteriosus, often involving the aortic isthmus
- Diminished systemic perfusion and increased LV afterload may result
- Clinical manifestations include cardiomegaly and pulmonary congestion
- Treatment involves emergent opening of the PDA and surgical repair
Cyanotic Congenital Heart Lesions
- Hypoplastic left heart syndrome (HLHS), which is underdevelopment of the left heart structures
- Total anomalous pulmonary venous return (TAPVR), where pulmonary veins drain into the systemic veins
- Tetralogy of Fallot (TOF), consisting of four components including pulmonary artery stenosis, ventricular septal defect, overriding aorta to the right, and right ventricular hypertrophy
- Truncus arteriosus, where a single great artery arises from the ventricles
- Transposition of the great arteries (TGA), where the aorta arises from the right ventricle and pulmonary artery from the left ventricle
- Pulmonary atresia with intact ventricular septum (PA/IVS), where blood flow out of the right ventricle is obstructed.
Hypoplastic Left Heart Syndrome (HLHS) (Part 1/3)
- Most or all left heart structures are underdeveloped including the mitral valve, left ventricle, aortic valve, and aortic arch
- Blood flow to the body depends on the right ventricle.
- This involves both a left to right shunt for pulmonary venous return and a right to left shunt for systemic blood flow
Hypoplastic Left Heart Syndrome (HLHS) (Part 2/3)
- Early diagnosis occurs prenatally or soon after birth
- Common presentations include premature closure of PDA (patent ductus arteriosus)-leading to immediate hypoperfusion, metabolic acidosis, and circulatory collapse.
Hypoplastic Left Heart Syndrome (HLHS) (Part 3/3)
- Treatment involves supporting patients with pulmonary edema and increased work of breathing using non-invasive ventilation (NIV)
- Prostaglandin E1, diuretics, and surgical repair including a stage 1 palliation (S1P) procedure are part of the management strategies
Total Anomalous Pulmonary Venous Return (TAPVR)
- Abnormalities where pulmonary veins drain to systemic venous circulation instead of the left atrium
- TAPVR may be supracardiac, cardiac, infracardiac or mixed
- Treatment involves HFOV or ECMO, and surgical repair to relieve pulmonary vein obstruction.
Tetralogy of Fallot (TOF)
- The most common cyanotic congenital heart abnormality
- Includes four components: pulmonary artery stenosis, ventricular septal defect, overriding aorta to the right, and right ventricular hypertrophy
Tetralogy of Fallot (TOF) (Infants)
- Infants with unrepaired TOF may exhibit hypercyanotic spells
- Acute RVOT obstruction leads to decreased pulmonary blood flow and decreased SpO2.
Truncus Arteriosus
- A rare defect in which a single great artery arises from the ventricles
- This artery supplies both pulmonary and systemic circulations
- Infants with unrepaired lesions may have respiratory distress, CHF (congestive heart failure) or shock from systemic hypoperfusion
Transposition of the Great Arteries (TGA)
- Aorta arises from the RV and the pulmonary artery arises from the LV
- Two circulations are in parallel, not in series
- Surgical repair is typically arterial switch operation
Pulmonary Atresia with Intact Ventricular Septum (PA/IVS)
- Blood flow from the RV is obstructed due to atresia of the pulmonary valve
- The RV is often hypertrophied with a hypoplastic cavity
- The left side of the heart receives blood from the right via ASD or patent foramen ovale.
- Pulmonary blood flow is ductal dependent.
- Treatment includes catheter-based dilation, PDA stenting, or surgical placement of a BTS
Clinical Monitoring of Patients With Cardiac Anomalies (Part 1/2)
- Hemodynamic monitoring is suggestive of a low stroke volume with narrowed pulse pressure.
- Pulse oximetry and Co-oximetry to assess oxygenation and blood flow
- Measurement of end-tidal carbon dioxide (ETCO2) with capnography can be useful for evaluating various conditions like endotracheal tube dislodgment, air trapping, and hyperventilation.
Clinical Monitoring of Patients With Cardiac Anomalies (Part 2/2)
- Capnography measures ETCO2, which can be used as a surrogate to evaluate CPR (cardiopulmonary resuscitation)
- Increased gradients between Paco2 and ETCO2 can indicate various cardiopulmonary conditions, including reduced pulmonary blood flow
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Description
Test your knowledge on congenital heart defects, including total anomalous pulmonary venous return (TAPVR), Tetralogy of Fallot, and Truncus Arteriosus. This quiz covers key concepts, clinical features, imaging findings, and management strategies related to these conditions. Perfect for students and professionals in the medical field!
