24 - Congenital Heart Diseases

Auscultation locations and what we listen for

A: 2nd ICS right sternal border → Aortic valve sounds

P: 2nd ICS left sternal border → Pulmonary valve sounds

T: 4-5th ICS left sternal border → Tricuspid valve

M: 5th ICS midclavicular line → Mitral valve

Simple patient history for congenital and acquired heart disease?

1. Congenital: Patients will have murmurs/symptoms since birth

2. Acquired: The patient is healthy for a few years

Congenital heart disease big types

Cyanotic and acyanotic

Acyanotic heart disease main types

• L to R shunt

• Obstructive lesions

• AV valve regurgitation

Why does a L-R shunt happen, and why is the patient not cyanotic?

• Because the LV has a higher pressure than the LA

• The pt. isn’t cyanotic because no dexoygenated blood travels thru the aorta, but oxygenated blood will go to the lungs more

3 types of L-R shunts

VSD, ASD, PDA

VSD

• Mechanism and results along the way

• VSD starts with a hole in the interventricular septum which allows blood from the high pressure LV to get into the lower pressure RV which increases blood to the lungs, meaning more blood returns to the LA/LV → LA/LV enlargement

  • Once this happens for a while, the heart can’t pump out all the extra volume and causes CHF and eventually pulmonary hypertension → tachypnea, dyspnea in feeding, poor weight gain, peripheral edema

  • If the hole is small, pt. can be asymptomatic

ASD

• Mechanism and results along the way

• ASD starts with a hole between the atria, and flow goes from LA to RA, and that blood goes to the RV → RA/RV enlargement

  • Symptoms show up slower than VSD, and many pt. are asymptomatic into adult hood but eventually right-sided CHF can happen → fatigue on exertion, leg swelling, hepatomegaly, raised JVP → pulmonary hypertension but rarer

PDA

• Mechanism and results along the way

• In fetus, the ductus arteriosus helps connect the blood going from pulmonary artery to the aorta because the lungs have high pressure

  • Once the fetus is born, O2 starts coming in and the ductus arteriosus typically closes off within the first week

  • Now, the aorta has higher pressure than the PA, so oxygenated blood now flows from aorta to PA, goes to lungs, and returns to the LA and LV → LA/LV enlargement

  • If the duct is small, it could be asymptomatic, but larger ones can cause volume overload and CHF, and pulmonary hypertension can develop

Eisenmenger syndrome summary

Right sided pressure eventually gets higher than left side because of pulmonary hypertension, so deoxygenated blood gets to where oxygenated blood should be → cyanosis

Main obstruction cause of acyanotic heart disease

Coarctation of aorta

Coarctation of aorta

• Mechanism and results along the way

• The aorta has a part where it narrows, after the exit of the L subclavian artery → This causes higher pressure in the aorta before the obstruction since it has to try to push through, and the LV has to pump harder → LVH

  • As a result of the obstruction, less blood gets to the lower extremities → High upper extremity BP vs low lower extremity BP

Preductal vs postductal coarctation of aorta

Preductal: Before insertion of ductus arteriosus, so the lower body also gets blood from the RV

Postductal: After insertion of ductus arteriosus, which means that the blood the lower body gets is from what gets through the obstruction

Type A interrupted aortic arch

• Aortic arch has a total gap from the descending aorta after the subclavian(L) exit → LV blood can’t get to lower body at all

  • Body uses ductus arteriosus only to push blood to lower body

How are cyanotic heart disease split and what are their differences?

1. Increased pulmonary flow: Oxygenated and deoxygenated blood mix and go to the lungs → cyanosis is mild

2. Decreased pulmonary flow: Something stops blood getting to lungs, not enough blood is oxygenated → cyanosis is marked

3. Parallel circulation: Aorta and PA are swapped → GGs

Truncus arteriosus

• Mechanism and results along the way

• In truncus arteriosus, the aorta and pulmonary artery combine to form a “truncus” that hangs over a VSD, so oxygenated blood and dexoygenated blood from LV/RV get in together

  • The pulmonary artery is now a branch of the truncus which then becomes the aorta → RV “steals” blood from the aorta when diastole should be happening(Low DBP) and less blood is available for the body(Cyanosis), and the increased blood flow into the lungs causes pulmonary overcirculation and pushes more blood into the LA/LV → volume overload and CHF

What condition is truncus arteriosus associated with?

DiGeorge syndrome: Deletion on Chr. 22 → truncus arteriosus, cupped ears/fish mouth, cleft-palate, hypoCa+

Tetralogy of Fallot

• Mechanism and results along the way

• ToF starts with a VSD that lifts up and to the right → This causes the aorta to override both LV and RV, the RV outflow tract to be compressed

  • Now, the compressed RV outflow tract has higher pressure than the VSD path into the overriding aorta, so less blood goes to the lung(Less oxygenated blood) and more deoxygenated blood goes to the body → Cyanosis, and the body also adapts to the pressure via RVH

Key symptoms associated with ToF

Squatting, hypoxic spells during feeding/crying/waking

Transposition of the great arteries

• Mechanism and results along the way

• During development, the aorta now attaches to the RV and the pulmonary artery now attaches to the LV

  • As a result, oxygenated blood from the lungs just goes back to the lungs while deoxygenated blood from the body keeps going out to the body

What does the body need to compensate for TGA?

Intracardiac mixing via VSD, ASD, foramen ovale so that the oxygenated blood from lungs can mix into the RV, and for deoxygenated blood from the body can mix into the LV to get oxygenated

Cardinal signs of CHF in children and their causes

1. Tachypnea: Left side overload leakins into lungs and it brings in less air

2. Tachycardia: Tissues don’t get enough blood → Increased HR to compensated

3. Hepatomegaly: From back-pressure of the right side

4. Cardiomegaly: Volume overload causes dilation