Congenital Heart Diseases

Question 1

Normal formation of heart loop diagram

Answer 1

Question 2

Atrial septal formation diagram

Answer 2

Question 3

Developmental atrial flap valve

Answer 3

Question 4

Interventricular foramen

Answer 4

Remains open until 7th week gestation when the membranous septum forms

Question 5

Papillary muscle and cordae tendinae development

Answer 5

Question 6

Fetal circulation

Answer 6

Question 7

Why are most congenital heart defects unnoticed until birth?

Answer 7

Because most of them are bypassed by fetal circulation

Question 8

Cyanotic vs acyanotic

Answer 8

Causing cyanosis vs not

ie

Shunting past lung vs not

ie

Right-to-left shunt vs left-to-right shunt

Question 9

Left-to-right shunt reversal

Answer 9

Elevated pulmonary resistance due to an early life left-to-right shunt may result in a change in shunt direction, accompanied by cyanosis and hypoxemia.

Question 10

Aside from pathology resulting from their anatomy, patients with congenital heart disease are susecptible to ___.

Answer 10

Aside from pathology resulting from their anatomy, patients with congenital heart disease are susecptible to bacterial endocarditis

Question 11

Atrial septal defect

Answer 11

Question 12

Most common atrial septal defect

Answer 12

Ostium secundum defect

Question 13

Ostium primum defect

Answer 13

Failure of the septum primum to fuse with the endocardial cushions, resulting in atrial sepatl defect.

Question 14

Sinus venosus defect

Answer 14

Loss of the roof of the right atrium due to improper development of the pulmonary veins, resulting in a right atrium -> pulmonary vein -> left atrium shunt.

Question 15

Patent foramen ovale

Answer 15

In ~20% of the general population, but doesn’t functionally matter as long as the LA pressure is greater than the RA pressure. However, if there is, for example, increase in right heart afterload resulting in backward increase in RA pressure, the patent foramen ovale may reopen. This results in a right->left cyanotic shunt

Question 16

Paradoxical embolism

Answer 16

When a thrombus in the venous system and shoots to the RA, through the foramen ovale, and into systemic arterial circulation.

Question 17

___ also helps drive right-to-left atrial shunts.

Answer 17

High right ventricular compliance also helps drive right-to-left atrial shunts.

Right ventricular compliance increases after birth due to regression of the RV.

Question 18

Atrial septal defect physical exam

Answer 18

• S2 splitting
• Systolic murmur (pansystolic)
• Mid-diastolic murmur may be present (due to increased tricuspid valve flow)
• Blood traversing the ASD itself does not produce a murmur because of the absence of a pressure gradient between the two atria

Question 19

Treatment for ASDs

Answer 19

Most people are asymptomatic, but for those who are symptomatic, elective surgery is recommended to prevent heart failure.

Question 20

Ventricular septal defect

Answer 20

Question 21

Ventricular septal defects often result in ___ which mediates the chronic disease pathology.

Answer 21

Ventricular septal defects often result in eccentric hypertrophy of the left ventricle which mediates the chronic disease pathology.

Question 22

Ventricular septal defects on physical exam

Answer 22

• Harsh holosystolic murmur
• Palpable systolic thrill over left sternal border
• Mid-disatolic rumble over apex due to increased flow through mitral valve
• If there is shunt reversal due to pulmonary vascular disease, a loud P₂ and cyanosis may be appreciated

Question 23

Treatment of ventricular septal defects

Answer 23

• By 2 years of age, 50% of small to midsized VSDs will spontaneously close or close to the point that they are asymptomatic
• Surgical correction recommended for extreme cases (congestive heart failure or pulmonary vascular disease) and for those that fail to close after ~2 years

Question 24

Patent ductus arteriosus

Answer 24

Question 25

Patent ductus arteriosus on physical exam

Answer 25

• Continuous, machine-like murmur (pressure gradient exists between the aorta and pulmonary artery in both systole and diastole)
• Best heard in the left subclavicular region
• If there is shunt reversal, cyanosis and clubbing may be present

Question 26

Congenital aortic stenosis

Answer 26

Question 27

Congenital pulmonic stenosis

Answer 27

Question 28

Coarctation of the aorta

Answer 28

Question 29

Tetralogy of Fallot

Answer 29

Question 30

Transposition

Answer 30

Question 31

Eisenmenger Syndrome

Answer 31

The left-to-right -> right-to-left shunt shift

• Thrombosis within the pulmonary vessels is a major mechanism increasing the pulmonary resistance
• Patients are cyanotic with digital clubbing
• Prominent a wave on JVP, reflecting elevated RA pressure

Question 32

Transposition is treated with. . .

Answer 32

. . . emergency surgery to create an atrial septal defect.

This allows for mixing of the parallel circuits of blood and allows the oxygen saturation to improve enough to get to surgical repair.

In utero, the fetus is kept alive through flow through the ductus arteriosus and foramen ovale.

Question 33

An infant is cyanotic at birth. A chest x-ray is taken. What is the likely diagnosis?

Answer 33

Transposition

You can tell from the ‘box-like’ mediastinum, which is due to the lack of proper conotruncal twist

Question 34

The only oxygenated coronary bloodflow from a transposition heart comes from ___.

Answer 34

The only oxygenated coronary bloodflow from a transposition heart comes from the associated atrial septal defect.

Question 35

Atrial septostomy

Answer 35

Surgical foration of an atrial septal hole. Can be done in the cath lab in emergency situations, like cyanosis from transposition without availability of PGE₁ or a surgeon available for immediate open heart surgery.

Question 36

An infant has low oxygen saturation, decreasing even lower with crying. A chest X-ray is taken. What is the likely diagnosis?

Answer 36

Tetralogy of fallot

This is a tough one. The main findings are 1. a right-sided aortic arch and 2. substantially decreased pulmonary vascular markings.

The right sided arch is actually fairly common with multiple conotruncal defects, but the vascular markings are telling. There is not much pulmonary bloodflow due to high pulmonary resistance, hence the decreased markings.