Overview of Pediatric Echocardiography Assessment, Protocols, and Interpretation
Echocardiography is a non-invasive way doctors evaluate and manage heart issues. Basically, it’s an ultrasound of the heart that lets doctors see the mechanics of the heart, like its structure, function, and blood flow. This procedure is a common tool for heart doctors worldwide.
Now, when we talk about echocardiography, it’s a broad term that covers many different types of heart ultrasounds. These include transthoracic echocardiography (TTE), stress echocardiography, transesophageal echocardiography, fetal echocardiography, three-dimensional echocardiography, intracardiac echocardiography, Intra-valvular echocardiography, and Intra-operative echocardiography.
In this summary, we will focus on Pediatric Transthoracic Echocardiography (TTE), a reliable way to test for kids. In one study, out of 50,660 TTEs performed, only 87 were misdiagnosed. We’ll be discussing two types of TTEs: comprehensive transthoracic echocardiography (cTTE) and functional transthoracic echocardiography (fTTE). And, we’ll highlight how these pediatric procedures are different from TTEs performed on adults. Lastly, since 4 to 12 out of every 1000 babies are born with a heart defect (also called congenital heart disease), we’ll discuss it too.
Anatomy and Physiology of Pediatric Echocardiography Assessment, Protocols, and Interpretation
Like in adults, a medical procedure known as Transthoracic Echocardiograms (TTEs) is used for children to examine the structure of the heart. However, for children, especially those with a complex Congenital Heart Disease (CHD), which is a birth defect that affects the heart’s structure and function, it’s a bit more difficult. This difficulty arises due to the unusual appearances of certain heart structures in CHD. Therefore, when doing a TTE on children, it’s very important to carefully notice the distinct features of the heart’s structure.
For more careful examination, three specific areas around the chest are studied: the suprasternal notch, which is the hollowed area in the neck where it meets the chest; the right parasternal, which is the right side along the breastbone; and the subxiphoid, an area just below the tip of the breastbone. These areas provide us with different views of the heart.
For your understanding, here are some of the specific features of parts of the heart, including major blood vessels:
- The atria—Right atrium (RA) is in the front and has a broad, triangular extended part; the left atrium (LA) is at the back and has a thin, long extended part.
- The atrial septum—the right has a valve named the Eustachian Valve; the left has a hole known as the foramen ovale.
- The ventricles—Right ventricle (RV) has thick inner walls, a three-flap valve, and a bandlike structure called the moderator band; the left ventricle (LV) has thin inner walls, a two-flap valve, and does not have a moderator band.
- The tricuspid valve—is connected to the RV, has three flaps, and is closer to the heart’s pointy end.
- The mitral valve—is connected to the LV, has two flaps, and is physically connected to the heart’s side wall by other little muscles (papillary muscles).
- The aorta—is a large blood vessel that carries blood from the heart and provides it to the body. It also supplies the coronaries which are special blood vessels that provide blood to the heart muscle.
- The pulmonary artery—splits into two major branches for the right and left lung where it carries blood from the heart to the lungs for oxygenation.
The different views, or ways the heart is looked at during the TTE, let us see different things, including size and function of all heart chambers, function of tricuspid and mitral valve, flow of blood across heart valves and the caliber of Right Coronary Artery (RCA) and Left Coronary Artery (LCA). They also provide visibility of other structures and organs such as stomach, spleen, and veins entering and leaving the heart.
Why do People Need Pediatric Echocardiography Assessment, Protocols, and Interpretation
According to the 2014 guide from the American College of Cardiology (ACC), certain signs in children can tell doctors that they need to carry out a detailed examination of the child’s heart. This can be a type of ultrasound called a cTTE (a heart scan). For instance, these can include:
- Irregular heartbeat, if the child’s family has a history of heart muscle disease or if there was a sudden death or heart attack in the family before the age of 50.
- An unusually fast heartbeat if the ECG (a heart test) shows certain types of fast heart rhythms.
- Fainting, especially if it happens during or after physical effort, if there’s an abnormal ECG, or if there’s any family history of heart muscle disease or early sudden death or heart attack.
- Chest pain when exercising or if the ECG is abnormal, or if there’s a family history of heart muscle disease or unexpected death.
- A heart murmur if the child has a history of heart disease or the murmur sounds abnormal.
- Bluish skin (cyanosis) or signs of a heart infection, regardless of the results from blood tests.
- Heart failure symptoms.
Also, a detailed heart scan may be needed if children show signs of disorders that can affect the heart, like Kawasaki disease, systemic hypertension, kidney failure, Human Immunodeficiency Virus (HIV) infection, and more. It can also be required if there are abnormalities in previous heart tests or if the child’s parents or siblings have certain types of heart disease, such as hypertrophic or non-ischemic dilated cardiomyopathy, a genetic disorder that can increase the heart disease risk (e.g., Loeys Dietz, Marfan), or an inheritable type of high blood pressure in the lungs.
Meanwhile, the 2020 ACC guide provides indications for heart scans in children with congenital heart diseases (heart problems present at birth). These include “single ventricle heart disease,” “Tetralogy of Fallot,” “pulmonary atresia with intact ventricular septum,” and more. But for some conditions, a routine heart scan may not always be needed, such as an asymptomatic patient with a silent Patent Ductus Arteriosus, or a patient with Pulmonary Hypertension that has been treated and is stable.
Equipment used for Pediatric Echocardiography Assessment, Protocols, and Interpretation
All machines used for an ultrasound scan of the heart (known as a cTTE) should be equipped with software that can handle basic 2D imaging, M-mode, color flow Doppler, and spectral Doppler. The specifics of each method are explained further in the sections below.
Ultrasound probes work by sending out mechanical electrical waves, sort of like invisible sound waves. This is done by sending an electrical current through some clever pieces of tech called piezoelectrical crystals. When these crystals are electrified, they start making sound waves. These waves then travel through whatever they’re sent into – in this case, your body – at different speeds depending on what they’re travelling through. The waves then bounce back to the crystals and turn back into a form of electricity. This electrical signal can then be turned into images, which is how they make a 2D echo image of your heart.
The ultrasound probes can also make what’s called a Doppler image. This is like a normal image, but it shows movement as different colours. If something in your body, like your blood, is moving away from the probe, it shows up as blue. If it’s moving towards the probe, it shows up as red. There’s a kind of Doppler image called a spectral Doppler that shows the average and peak speeds of the moving thing – this is shown on a graph to make it easier to understand. There’s another kind called a tissue Doppler, which shows how fast the heart muscle is moving.
The great thing about ultrasounds is that they don’t use any harmful radiation, which makes them safe to use on everyone, including children and unborn babies. There are different types of probes that can be used depending on the patient. For small infants, for example, there’s a high frequency probe that provides really detailed images of the top layers of the body.
Preparing for Pediatric Echocardiography Assessment, Protocols, and Interpretation
Before the test, children may be asked to not eat or drink anything for 6 to 8 hours. This is because younger ones may need gentle sedation to help them remain calm during the procedure. During the test, the child will be asked to lie down on a table or bed, with the head slightly raised. If possible, lying on their side could provide clearer images due to how gravity influences the position of the heart.
For infants, it might be easier if a parent holds them throughout the process. Tools to distract the child may also be provided if necessary. A few tiny sensors (electrodes) will be placed on the child to record heart activity during the test.
It’s important to expose the left side of the child’s chest, so the gown will be adjusted accordingly. For teenagers, a towel will be provided for discretion. The doctor will then apply a special gel on a small device (probe) to help capture clear images of the heart, and then the test will begin.
How is Pediatric Echocardiography Assessment, Protocols, and Interpretation performed
The process of running a cTTE (transthoracic echocardiogram) exam is generally ordered for a reason. The steps required are usually outlined by the hospital or clinic, allowing the doctor to have a structured way of conducting all echocardiograms. This strategy makes it easier to interpret each cTTE. For children, ensuring you recognize fundamental anatomy is key in identifying or ruling out congenital heart disease (a birth defect that affects how the heart works). The process begins with a subcostal view, which means looking at the heart from just below the rib cage, to identify the heart’s pointy end (the apex), chambers (ventricles), and major blood vessels. Once the heart’s layout is understood, the medical professional will systematically move the ultrasound probe in a clockwise direction to view the heart from different angles.
On the other hand, an fTTE (focused transthoracic echocardiogram), also referred to as a bedside TTE, doesn’t follow a particular technique. It’s performed quickly to check the basic structure and function of the heart. Some fTTE machines may not have features like dopamine or ECG gating, which help assess blood flow and heart electrical activity. The doctor mostly uses the apical and subcostal viewing windows in the body – meaning they look at the heart from beneath the apex or just below the rib cage.
What Else Should I Know About Pediatric Echocardiography Assessment, Protocols, and Interpretation?
Transthoracic echocardiograms, often referred to as TTEs, are commonly used as diagnostic tools for observing the heart. They have proved helpful in diagnosing conditions in four major categories, including specific conditions in children, diseases viewed from different angles around the heart, measurements for specific parts of the heart, and use in intensive care units.
TTEs use different types of imaging to examine the heart:
1. 2D imaging: This real-time imaging provides a closer look at the structure and movement of the heart.
2. M Mode: This creates still images that help measure the size of the heart walls and chambers.
3. Doppler: This is used to observe the flow of blood through the heart. A color Doppler assesses the direction of flow, while spectral Doppler evaluates the pressure inside the heart.
When performing a TTE, the heart is looked at from different angles, known as “views”, that can help point out various issues:
1. Parasternal Long Axis and Short Axis: These views can identify problems with the heart’s valves and chambers.
2. Apical View: This view examines abnormalities in the heart valves and measures the size and function of the left ventricle.
3. Subcostal Short and Long Axis: These views can reveal issues with veins, abnormal drainage, and problems with the heart chambers.
4. Suprasternal Notch View: This view can identify issues with the veins, the aorta, and vessels in the head and neck.
TTEs also provide critical measurements related to different parts of the heart, such as valve diameter, velocity of blood flow, and the thickness of the heart walls. These measurements help healthcare professionals assess the child’s heart health compared to average values, allowing them to detect any abnormalities.
In neonatal and pediatric intensive care units, TTEs are specifically used to evaluate conditions like pulmonary hypertension, analyze cardiac function, assess the body’s fluid balance, diagnose heart-related issues, and check the placement of medical equipment such as central lines. In summary, this tool is essential for diagnosing and monitoring heart conditions in children.
