09.01 Congenital Heart Defects (CHD)

Hey you guys, In this lesson we are going to talk about the basics of congenital heart defects.

Congenital heart defects are abnormalities in the heart's structure. These are present from birth and not acquired like the damage that might occur from something like rheumatic fever.

These defects are associated with other syndromes and chromosomal abnormalities. Down Syndrome and Turner Syndrome are two of the most common syndromes to have heart defects.

Risk factors that may contribute to their development in utero are, family history, maternal diagnosis like diabetes or lupus, maternal use of drugs and alcohol, maternal exposure to rubella and exposure to teratogenic medications like phenytoin.

So, I just want to quickly review a few things.

The first is that the pressure in the left side of the heart is normally greater than the right side of the heart. This means that when there are openings in the heart the blood is naturally going to move, or shunt from left to right.

Also, babies have two extra holes in their heart. The foramen ovale and the ductus arteriosus. These should close at birth due to pressure changes. Check out the lesson on fetal circulation for more on this, but for our purposes you need to know that when these remain open, deoxygenated blood and oxygenated blood mixes. .

There’s a lot to digest with this topic and one way to help with this is to classify the defects. Back in the day, they were just classified as being acyanotic or cyanotic. We don’t really use this anymore because it oversimplifies things and really any heart defect can cause cyanosis if they go untreated for long enough.

The more helpful way to classify is to think about hemodynamics or how the defect affects the way blood moves through the heart.

Heart defects may 1) cause increased blood flow to the pulmonary 2) cause a decrease in the amount of blood flowing through the pulmonary system, 3) obstruct the flow of blood 4) or the blood may mix, meaning oxygenated blood mixes with deoxygenated blood.

Let’s take a look at these categories and the defects.

Atrial Septal Defect, Ventricular Septal Defect , Atrioventricular Canal Defect and Patent Ductus Arteriosus are all abnormal openings in the heart that cause increase pulmonary blood flow.

Tetralogy of Fallot and Tricuspid Atresia cause decreased pulmonary blood flow and used to be classed as cyanotic heart defects.

Coarctation of the aorta, Pulmonic Stenosis, and Aortic Stenosis all obstruct the flow of blood through the heart.

And Transposition of the Great Arteries, Truncus Arteriosus and Hypoplastic Left Heart cause the blood to mix. These are very complex defects. The key thing is that the patient depends on having an opening, like a PDA or ASD that allows the blood to mix.

We have lessons for each of these classifications for you!

Okay so this slide and the next will overlap with what you know about heart failure in adults so I’m just going to focus on what is different for kids.

So, you’re going to listen to the heart and check the rate and rhythm. With kids, bradycardia isn’t less than 60 bpm like it is with adults. For an infant less than 90-100 bpm would be bradycardia so make that mental adjustment when you are assessing HR in little ones.

When assessing perfusion, Remember capillary refill is our best indicator of perfusion so if it’s > 2 seconds they aren’t perfusing well. And always check pulses, radial or brachial and femoral.

Respiratory effort may be compromised if there is excess blood flow pumping to the lungs, so look for increased work of breathing and shortness of breath.

You already know to look for edema, so I just want to point out that in babies or non-mobile patients edema may present as periorbital or sacral because they aren’t up walking.

Okay this last part of the assessment is super important because it is one of the main things that’s different in kids. Cardiac problems in babies will often present as a feeding problem because it requires a ton of energy and is pretty much like an exercise stress test. So, anytime a baby is having a difficult time feeding we need to consider that the cause could be a heart defect.

This chart is just a refresher on the signs and symptoms of heart failure. I’ve highlighted those that are specific to kids.

As we go through all the different defects in the other lessons keep these symptoms in mind. Remember, we are classifying the defects according to their effect on blood flow, so you should be able to work through it logically to think about what symptoms you might see.

Treatment is a combination of surgery, cardiac catheterizations and medications. Medications given will be similar to those you use in adults and nursing care surrounding their administration is very much the same. One difference I want to highlight is that with digoxin you need the medication order to give specific heart rate parameters for when to give. Remember, 60 is not our parameter for bradycardia. It will be different for each age so we need the order to be very clear.

Nursing care for kids with heart defects are focused on these 4 major goals. We want to decrease cardiac demands, reduce respiratory distress or effort, support adequate feeding and monitor fluid and electrolytes.

Remember a major difference between babies and adults with heart failure is feeding difficulties. So energy needs to be conserved for eating and we want to minimise stress and crying around feeding. The optimal feeding routine is every 3 hours and the feeds shouldn’t last any longer than 30 minutes. If they take longer than that they are using too much energy.

The rest here is going to overlap with what you already know with adults. So if you need a refresher on heart failure check out the lessons that cover it in the med-surg cardiac course.

Your priority nursing concepts for a peds patient with a congenital heart defect are perfusion, oxygenation and nutrition.
This lesson is setting the stage for you to go on and learn about the specific cardiac defects. They are classified according to their impact on blood flow. So increased or decreased pulmonary blood flow, obstructed or mixed blood flow.

Risk factors for CHD are family history, maternal substance abuse, teratogenic medications and exposure to rubella while pregnant.

Your assessment should focus on looking for signs of decreased cardiac function or output, signs of pulmonary congestion and signs of systemic congestion. Remember, feeding for a baby is like exercise for adults so always take some time to watch a baby feed and look for signs of distress.

Treatment is a combination of surgery, cardiac catheterization and medications to manage heart failure.

Nursing care focuses on promoting rest and a lot of this is focused on creating a feeding schedule and keeping an eye out for signs of respiratory distress and fluid overload.

That's it for our lesson on Congenital Heart Defects. Make sure you check out all the resources attached to this lesson. Now, go out and be your best self today. Happy Nursing!