Atresia is defined as the congenital absence of a normal opening. In the case of tricuspid atresia, the tricuspid valve is not present resulting in a lack of communication between the right atrium and the right ventricle. Consequently, the right ventricle is small and underdeveloped. An associated ASD allows blood to be diverted from the right to the left atrium. Survival depends on the presence of a VSD or on the ductus arteriosus remaining open after birth in order for blood to reach the lungs.
Corrective surgery is done in a series of three stages. The first stage, performed in the first days of life, is known as a Shunt Operation. During this procedure, a small tube (shunt) is placed between the aorta and the branch pulmonary artery. This helps increase blood flow to the lungs. The second and third stages are collectively known as the Fontan Procedure. The second procedure, performed at approximately six months of age, creates a Bi-directional Cavo Pulmonary Connection (BCPC).
This involves connecting the superior vena cava to the right pulmonary branch artery. The BCPC allows the deoxygenated blood of the upper half of the body to flow directly to the lungs. The shunt placed during the first stage operation is also ligated at this time. The third and final stage is performed at approximately 12 months of age. During this procedure, the deoxygenated blood of the lower half of the heart is directed to the lungs. This is done by channeling the blood of the inferior vena cava through the right atrium to the right branch pulmonary artery.
What Is Normal Cardiac Anatomy?
When your child has a congenital heart defect, there's usually something wrong with the structure of his or her heart's structure.
Heart With Normal Cardiac Anatomy
When your child has a congenital heart defect, there's usually something wrong with the structure of his or her heart's structure.
The heart is composed of four chambers. The two upper chambers, known as atria, collect blood as it flows back to the heart. The two lower chambers, known as ventricles, pump blood with each heartbeat to the two main arteries (the pulmonary artery and the aorta). The septum is the wall that divides the heart into right and left sides. The atrial septum separates the right and left atria; likewise, the ventricular septum separates the two ventricles.
There are four valves that control the flow of blood through the heart. These flap-like structures allow blood to flow in only one direction. The tricuspid and mitral valves, also known as the atrioventricular valves, separate the upper and lower chambers of the heart. The aortic and pulmonary valves, also known as the arterial valves, separate the ventricles from the main arteries. Oxygen-depleted blood returns from the body and drains into the right atrium via the superior and inferior vena cavas. The blood in the right atrium then passes through the tricuspid valve and enters the right ventricle.
Next, the blood passes through the pulmonary valve, enters the pulmonary artery, and travels to the lungs where it is replenished with oxygen. The oxygen-rich blood returns to the heart via the pulmonary veins, draining into the left atrium. The blood in the left atrium passes through the bicuspid, or mitral, valve and enters the left ventricle.
Finally, the oxygen-rich blood flows through the aortic valve into the aorta and out to the rest of the body.
From Nemours' KidsHealth
- ECG (Electrocardiogram)
- Cardiac Catheterization
- A to Z: Tetralogy of Fallot
- When Your Child Needs a Heart Transplant
- If Your Child Has a Heart Defect
- Tetralogy of Fallot
- Patent Ductus Arteriosus (PDA)
- A to Z: Hypoplastic Left Heart Syndrome
- A to Z: Atrial Flutter
- A to Z: Patent Ductus Arteriosus (PDA)
- Coarctation of the Aorta
- Heart Murmurs and Your Child
- Ventricular Septal Defect
- Atrial Septal Defect
- Congenital Heart Defects
- Heart and Circulatory System
- Congenital Heart Defects Special Needs Factsheet
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An arrhythmia is an abnormal heart rhythm usually caused by an electrical "short circuit" in the heart.
The heart normally beats in a consistent pattern, but an arrhythmia can make it beat too slowly, too quickly, or irregularly. This can cause the heart muscle's pumping function to work erratically, which can lead to a variety of symptoms, including fatigue, dizziness, and chest pain.
What Causes Arrhythmias?
The heart has its own conduction system, or electrical system, that sends electrical signals around the heart, telling it when to contract and pump blood throughout the body. The electrical signals originate from a group of cells in the right atrium, called the sinus node. The sinus node functions as the heart's pacemaker and makes sure the heart is beating at a normal and consistent rate. The sinus node normally increases the heart rate in response to factors like exercise, emotions, and stress, and slows the heart rate during sleep.
However, sometimes the electrical signals flowing through the heart don't "communicate" properly with the heart muscle, and the heart can start beating in an abnormal pattern — an arrhythmia (also called dysrhythmia).
Arrhythmias can be temporary or permanent. They can be caused by several things, but also can occur for no apparent reason. Arrhythmias can be congenital (meaning kids are born with it), sometimes due to a birth defect of the heart but sometimes even when the heart has formed normally.
Other causes of arrhythmias in kids include chemical imbalances in the blood, infections, or other diseases that cause irritation or inflammation of the heart, medications (prescription or over-the-counter), and injuries to the heart from chest trauma or heart surgery. Other factors (such as illegal drugs, alcohol, tobacco, caffeine, stress, and some herbal remedies) also can cause arrhythmias.
Signs and Symptoms
Because arrhythmias can cause the heart to beat less effectively, blood flow to the brain and to the rest of the body can be interrupted. If the heart is beating too fast, its chambers can't fill with the proper amount of blood. If it's beating too slowly or irregularly, the proper amount of blood can't be pumped out to the body.
If the body doesn't get the supply of blood it needs to run smoothly, these symptoms can occur:
- palpitations (a feeling of fluttering or pounding in the chest)
- shortness of breath
- chest pain
Arrhythmias can be constant, but usually come and go at random. Sometimes arrhythmias can cause no detectable symptoms at all. In these cases, the arrhythmia can only be discovered during a physical examination or a heart function test.
What's a Normal Heart Rate?
Heart rate is measured by counting the number of beats per minute. Normal heart rate varies depending on factors like age and whether the person leads an active lifestyle or not. (For example, athletes often have a lower resting heart rate).
The resting heart rate decreases as kids get older. Typical normal resting heart rate ranges are:
- babies (birth to 3 months of age): 100–150 beats per minute
- kids 1-3 years old: 70-110 beats per minute
- kids by age 12: 55-85 beats per minute
Your doctor should help you determine whether or not your child's heart rate is abnormally fast or slow, since the significance of an abnormal heart rate depends on the situation. For example, an older child or adult with a slow heart rate might begin to show symptoms when his or her heart rate drops below 50 beats per minute. However, trained athletes have a lower resting heart rate — so a slow heart rate in them isn't considered abnormal if no symptoms are associated with it.
Types of Arrhythmias
There are several types of arrhythmias, including:
Premature Atrial Contraction (PAC) and Premature Ventricular Contraction (PVC)
Premature contractions are usually considered minor arrhythmias, in which the person may feel a fluttering or pounding in the chest caused by an early or extra beat. PACs and PVCs are very common, and are what happens when it feels like your heart "skips" a beat. It doesn't skip a beat — an extra beat actually comes sooner than normal. Occasional premature beats are common and considered normal, but in some cases they can indicate an underlying medical problem or heart condition.
Tachycardias are arrhythmias that involve an abnormally rapid heartbeat. They fall into two major categories — supraventricular and ventricular:
- Supraventricular tachycardia (SVT): is the most common significant arrhythmia, it's characterized by bursts of fast heartbeats that originate in the upper chambers of the heart. The bursts can happen suddenly, and episodes can last anywhere from a few seconds to several days. Specific treatment is usually recommended if incidents of SVT are long-lasting or happen often.
- Ventricular tachycardia: is a serious but relatively uncommon condition that originates in the lower chambers of the heart and can be dangerous.
Bradycardias — arrhythmias characterized by an abnormally slow heartbeat — include:
- Sinus node dysfunction: is when the heart's sinus node isn't working correctly, most commonly following surgery to correct a congenital heart defect. An abnormally slow heartbeat is typically seen in this condition; however, episodes of rapid heartbeat due to SVT also can occur.
- Heart block: is often caused by a congenital heart defect, but also can be the result of disease or injury. Heart block happens when electrical impulses can't make their way from the upper to lower chambers of the heart. When this happens, another node in the lower chambers takes over and acts as the heart's pacemaker. Although it sends out electrical impulses to keep the heart beating, the transmission of the signals is much slower, leading to a slower heart rate.
Doctors use several tools to diagnose arrhythmias. It's very important to know your child's medical history and give this information to your doctor, who will use it, along with a physical examination, to begin the evaluation.
If an arrhythmia is suspected, the doctor will probably recommend an electrocardiogram (EKG) to measures the heart's electrical activity. There is nothing painful about an EKG — a series of electrodes (small metal tabs) are fixed to the skin with sticky papers, then information about the electrical activity of the heart is transferred to a computer, where it's interpreted and drawn as a graph.
The doctor might recommend the following types of EKG tests:
- Resting EKG. This measures resting heart rate and rhythm, and lasts about a minute.
- Exercise EKG (also called a stress test). This measures heart rate and rhythm while exercising, like riding a stationary bicycle or walking on a treadmill.
- Signal-average EKG. This measures heart rate much like a resting EKG. The only difference is the signal-average EKG monitors the heartbeat over a longer time period (around 15–20 minutes).
- Holter monitor. This is an EKG done over a long period of time, usually 24 hours or more. The electrodes are connected to the chest, and the wires are attached to a portable EKG recorder. The child is encouraged to continue normal daily activities, but must be careful to not get the electrodes wet (for example, no swimming, showering, or activities that cause a lot of sweating). The two kinds of Holter monitoring are: continuous recording, which means the EKG is on throughout the entire monitoring period; and event monitoring, which means data is recorded only when the child feels symptoms and then turns the Holter monitor on.
Many arrhythmias don't require treatment; however, some can pose a health problem and need to be evaluated and treated by a doctor.
Depending on the type and severity of the arrhythmia, one of these options might be recommended:
- Medications. Many types of prescription anti-arrhythmic medications are available to treat arrhythmias. The doctor will determine which is best by considering the type of arrhythmia, possible underlying medical causes, and any medications a child is taking. Sometimes, anti-arrhythmic medications can increase symptoms and cause unwanted side effects, so their use and effectiveness should be closely monitored by the doctor, you, and your child.
- Pacemakers. A pacemaker is a small, battery-operated device implanted into the body (near the collarbone) through a surgical procedure. Connected to the heart by a wire, pacemakers can help treat bradycardia. Through a sensing device, a pacemaker can detect if the heart rate is too slow and sends electrical signals to the heart to speed up the heartbeat.
- Defibrillators. Like a pacemaker, a defibrillator can deliver electrical impulses to the heart. A small battery-operated implantable cardioverter defibrillator (ICD) can be implanted near the left collarbone through a surgical procedure. Wires run from the defibrillator to the heart. It senses if the heart has developed a dangerously fast or irregular rhythm and delivers an electrical shock to restore a normal heartbeat.
- Catheter ablation. "Ablation" literally means removal or elimination. In the case of catheter ablation, a catheter (a long, thin wire) is guided through a vein in the leg to the heart. Arrhythmias are often caused by microscopic defects in the heart muscle. Once the problem area of the heart is pinpointed, the catheter heats or freezes the muscle cells and destroys them.
- Surgery. Surgery is usually recommended only if all other options have failed. In this case, the child is put under anesthesia, the chest is opened, and the heart is exposed. Then, the tissue causing the arrhythmia is removed.
When to Call the Doctor
Although many arrhythmias are minor and don't represent a significant health threat, some can indicate a more serious problem. If your child has been having symptoms of an arrhythmia, call your doctor.
Reviewed by: Joel D. Temple, MD
Date reviewed: September 26, 2016