(17) Complex Congenital Defects and Syndromes Lecture Review

What is the American Society of Echo term for defects requiring surgery within the first year of life?

Critical Congenital Heart Disease (C-CHD)

Why do most C-CHD cases not present symptoms until after $48$ hours of life?

Due to the time it takes for the hemodynamic shift from fetal to neonatal circulation

What specific screening test is used for newborns to detect suspected C-CHD?

Pulse oximetry test

What are three clinical symptoms of Critical Congenital Heart Disease?

Tachypnea, cyanosis, and heart murmurs

Which condition is characterized by a distinctly underdeveloped left ventricle with severe mitral and aortic valve hypoplasia?

Hypoplastic Left Heart Syndrome (HLHS)

In Hypoplastic Left Heart Syndrome, what is the direction of flow through the PFO?

Left to right

Why is a patent ductus arteriosus (PDA) required in Hypoplastic Left Heart Syndrome?

To allow blood to move from the pulmonary artery into the aorta via Right to Left shunting in systole

Reversed flow in which vessel is a strong indication of left heart obstruction?

The ascending aorta

What are the three parts of the Norwood procedure for surgical correction of HLHS (hypoplastic left heart syndrome)?

Part 1: Atrial septectomy, aorta reconstruction, and Blalock Taussig shunt; Part 2: Glenn shunt; Part 3: Fontan procedure

What is the purpose of the Blalock Taussig shunt in the Norwood procedure?

To connect the subclavian artery to the pulmonary artery

What connection is made during the Glenn shunt (Part 2 of the Norwood procedure)?

The SVC is connected to the right pulmonary artery

What connection is made during the Fontan procedure (Part 3 of the Norwood procedure)?

The IVC is connected by a conduit to the right pulmonary artery

What is the most common location for Coarctation of the Aorta?

Just distal to the left subclavian origin at the aortic isthmus

What is the definition of the aortic isthmus?

The small segment between the origin of the left subclavian and the area where the ductus connects to the aorta

What tissue layer forms the "shelf" that causes obstruction in Coarctation of the Aorta?

Tunica media

What is a common cause of Coarctation of the Aorta in adults?

Takayasu arteritis

How does blood pressure in the upper extremities change if coarctation occurs proximal to the left subclavian artery origin?

The left arm blood pressure may be significantly reduced compared to the right arm

What percentage of Coarctation of Aorta cases are associated with a bicuspid aortic valve?

$$50-80\%$$

Apart from bicuspid aortic valve, what other valvular condition is associated with Coarctation of the Aorta?

Mitral Valve Prolapse (MVP)

What Doppler velocity at the site of coarctation indicates significant obstruction?

$$> 1.5\,m/s$$

What is the characteristic Doppler flow appearance distal to a coarctation?

Continuous flow throughout diastole with a sawtooth appearance

What type of flow is demonstrated in the abdominal aorta when coarctation is present?

Low velocity, low resistance monophasic flow with continuous antegrade flow throughout the cardiac cycle

Which defect is considered the most extreme form of coarctation?

Interrupted Aortic Arch

What is required for blood flow to reach the abdomen and lower extremities in an Interrupted Aortic Arch?

A Patent Ductus Arteriosus (PDA)

How is Truncus Arteriosus defined?

A single large overriding outflow tract with a VSD and a single valve

How many leaflets typically comprise the single valve in Truncus Arteriosus?

$$5$$

In Truncus Arteriosus Type I, where does the main pulmonary artery originate?

From the trunk artery

What characterizes Type IV Truncus Arteriosus?

No pulmonary arteries are formed; only bronchial arteries originate from the descending aorta

In Truncus Arteriosus, which echocardiographic sweep cannot demonstrate two vessels exiting the ventricles?

The PLAX sweep

What characterizes d-Transposition of the Great Arteries (Complete TGA)?

The aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle

In d-Transposition, how do the great vessels appear as they exit the heart?

Parallel instead of crossed

Which echocardiographic view is preferred for diagnosing Transposition of the Great Arteries?

Parasternal short axis view

What is the Mustard/Senning procedure?

An atrial switch corrective surgery that uses baffles to guide flow into the proper ventricles

What occurs during an "Arterial switch" procedure for Transposition of Great Arteries?

The great arteries are cut and reinserted to the correct ventricles

In Complete Transposition, where is the aorta positioned relative to the pulmonary artery?

Anterior and rightward

Why are two parallel circuits in d-Transposition incompatible with life without a shunt?

Oxygenated blood is recycled to the lungs and deoxygenated blood is recycled to the body

What occurs in Corrected or L-Transposition?

Both the ventricles and the great vessels are reversed

In L-Transposition, which ventricle receives oxygenated blood from the left atrium?

The right ventricle

In L-Transposition, which vessel does deoxygenated blood exit through after leaving the left ventricle?

The pulmonary artery

What valve abnormality is most common in L-Transposition?

Ebstein anomaly or thick, dysplastic leaflets of the left atrioventricular valve

Which cardiac position is commonly associated with L-Transposition?

Dextrocardia

What are the four components of Tetralogy of Fallot (TOF)?

1. VSD, 2. Overriding aorta, 3. Pulmonary stenosis, 4. Right ventricular hypertrophy

What is the most common cyanotic abnormality identified in adults?

Tetralogy of Fallot (TOF)

What are "Tet spells"?

Rapid drops in blood oxygen levels causing blue nail beds, lips, and skin

What are signs of long-term cyanosis in TOF patients?

Clubbed fingers and discolored nail beds

Which echocardiographic view demonstrates the VSD, RVH, and overriding aorta in TOF?

Parasternal Long Axis (PLAX) View

What percentage of aortic override into the right ventricle is the threshold for diagnosing DORV instead of TOF?

$$> 50\%$$

What is the direction of VSD shunt flow in Tetralogy of Fallot?

Right to left

Why is it important to identify coronary artery origins before TOF surgery?

For surgeon during the procedure

What is a common chronic issue in patients after TOF repair?

Chronic pulmonary insufficiency leading to RV enlargement and dysfunction

Which procedure uses the patient's own pulmonary valve to replace a diseased aortic valve?

Ross procedure

What is the definition of Double Outlet Right Ventricle (DORV)?

Both the aorta and pulmonary artery originate from the right ventricle

What type of VSD is typically present in Double Outlet Right Ventricle?

Large subaortic VSD

What anatomical feature defines a Single Ventricle?

The interventricular septum is abnormal or missing

Which view best demonstrates a single ventricle defect?

Apical $4$ chamber view

What is Total Anomalous Pulmonary Venous Return (TAPVR)?

All pulmonary veins connect to a location other than the left atrium (usually the right atrium)

How is TAPVR ruled out during an echo?

By identifying at least one pulmonary vein entering the left atrium

What is the direction of flow through a PFO in TAPVR?

Right to left

What occurs in Partial Anomalous Pulmonary Venous Return (PAPVR)?

Some pulmonary veins connect to an abnormal location like the RA, IVC/SVC, or coronary sinus

What defect is associated with $80\%$ of PAPVR cases?

Sinus venosus ASD

What is the connection made in a Blalock-Taussig Shunt?

Subclavian or innominate artery connected to the pulmonary artery

Which view is best for evaluating a Blalock-Taussig Shunt?

Suprasternal view and high parasternal window

What is the purpose of the Fontan Procedure?

To connect systemic venous return to the pulmonary artery to increase flow in tricuspid atresia or single ventricles

What connection is made in a Rastelli Procedure?

Right ventricle to pulmonary artery

What is a pulmonary homograft in the context of a Ross procedure?

A pulmonary valve taken from a cadaver to replace the patient's original pulmonary valve

What is an Orthotopic cardiac transplant?

The native heart is removed and the donor heart is placed in its position

What is a Heterotopic cardiac transplant?

The donor heart is placed in the right chest adjacent to the native heart

Why do the atria appear enlarged in a post-transplant patient?

Due to the attachment of donor atria to native atria to preserve venous connections

What decrease in Ejection Fraction may indicate cardiac transplant rejection?

A decrease of $> 10\%$

Besides EF, what changes in the LV may indicate transplant rejection?

Increased left ventricular mass and varied myocardial echotexture

What new valvular finding can indicate transplant rejection?

New onset of mitral regurgitation

What diastolic filling pattern may indicate transplant rejection?

Restrictive diastolic left ventricular filling

In distinguishing ventricle morphology, which ventricle is bullet-shaped with smooth endocardium?

Left Ventricle

In distinguishing ventricle morphology, which ventricle has a moderator band and three papillary muscles?

Right Ventricle

Where is the Tricuspid Valve (TV) insertion relative to the Mitral Valve (MV)?

The TV insertion is closer to the apex of the heart