Overview of Electrophysiology Study and Ablation of Atrial Flutter
One of the biggest recent improvements in the field of heart health has been the fast development of transcatheter ablation techniques. This advancement has allowed doctors to treat irregular heart rhythms that were previously only manageable with potentially dangerous drugs or surgery. Now these can often be treated in the heart health (electrophysiology) laboratory.
Atrial flutter, a type of heart rhythm disorder, happens when the signals that control heartbeat get stuck in a sort of loop. This loop, or circuit, has to include some kind of barrier that makes the signal travel one way only. It also has to have an area where the signal travels slowly. This slow area can cause the heart tissue to recover and become available for new signals again. How a doctor treats atrial flutter with ablation depends on the specific type of flutter.
Transcatheter ablation is a procedure where doctors apply energy through a tube inserted into the heart, which creates a small, precise scar. This scarred area can then break the loop of the heart rhythm disorder and stop the flutter.
Anatomy and Physiology of Electrophysiology Study and Ablation of Atrial Flutter
Atrial flutter is a heart condition that can fall into two categories: typical or atypical. Typical atrial flutter relates to a specific part of the heart near the cavotricuspid isthmus (CTI), which is an area on the lower right side of the heart.
Counterclockwise CTI-dependent Atrial Flutter is a common variation of atrial flutter. It’s like an electrical circuit running in the wrong direction within the right side of the heart. The electrical signals move slowly between two main heart areas: the tricuspid valve (a valve that controls blood flow from the heart’s right upper chamber to the right lower chamber) and the coronary sinus (the vein that collects blood from the heart muscle). After a journey through various parts of the heart, it returns to the initial zone between the tricuspid valve and the coronary sinus. This abnormal path of electrical signals causes the heart to beat irregularly.
In the doctor’s tests, such as electrocardiogram or ECG (a test that measures the electrical signals in your heart), the irregular heartbeats appear as an abnormal pattern. This pattern helps the doctor identify the problem in the heart and the path it followed.
Another form of typical atrial flutter is Clockwise CTI-dependent Atrial Flutter – essentially, it’s the same abnormality as the Counterclockwise form, but the electricity flows in the opposite direction. The ECG readings for this type also show distinctive patterns. Both of these can be treated by a procedure called ablation, which destroys the tissue area causing the irregular heartbeat.
Atypical flutter is different; although it still includes a rerouting of the heart’s electrical path, it bypasses the usual CTI area. This form is often seen in patients who have undergone heart surgeries or have scar tissue in their hearts. It could also be caused by other conditions, like heart valve disease or a past heart-related procedure.
The indications of atypical flutter on an ECG test are varied. This type of flutter may switch back and forth with another heart rhythm condition called atrial fibrillation, and it can happen in either the right or left side of the heart. The ECG readings are critical for doctors to make the correct diagnosis and plan the best treatment strategy.
The site where the flutter originates can be determined by checking the heart’s internal electrical activation series. This information can help the doctor better understand the specific problem and how best to treat it. For example, early activation in certain areas suggests an origin in the right or left atrium of the heart.
Why do People Need Electrophysiology Study and Ablation of Atrial Flutter
In 2015, three major heart health organizations in the US came out with guidelines to help doctors manage patients who have an abnormal heart rhythm known as Supraventricular Tachycardia. These are as follows:
Highly Recommended Steps (Class I Indications)
– A procedure called Catheter Ablation on a part called CTI of the heart may be beneficial for patients whose AFL (a type of irregular heart rhythm) can’t be controlled with medication or if it is causing symptoms.
– This procedure is also useful for patients who continue to experience occasional AFL after an anti-arrhythmic medication (which controls heart rhythm) has not worked.
Reasonable Steps (Class IIa Indications)
– The procedure is sensible in patients whose AFL is triggered by certain medications (like flecainide, propafenone, or amiodarone) used to treat a different type of irregular rhythm.
– Also, performing the procedure on a part of the heart called the CTI is reasonable if patients who are already going to have heart ablation for AF (another irregular heart rhythm) also have a known history of clinical or induced CTI-dependent AFL.
– It is reasonable to consider the procedure for patients who keep having non–CTI-dependent AFL even before trying antiarrhythmic drugs, but potential risks and benefits need to be weighed.
Possibly Considered Steps (Class IIb Indications)
– The catheter ablation procedure might be a good choice for patients who have irregular heart rhythms but do not have symptoms.
When a Person Should Avoid Electrophysiology Study and Ablation of Atrial Flutter
Catheter ablation, a medical procedure used to correct heart rhythm problems, doesn’t have any absolute “no-go” scenarios. However, there are a few situations where it might not be the best option and should be thought through carefully:
Firstly, if a person has a bleeding disorder, or coagulopathy, which means their blood doesn’t clot properly, it can make this procedure risky. Another issue can be deep vein thrombosis; this is when a blood clot forms in a deep vein, usually in the leg. It could make it difficult for doctors to get vascular access, or reach the veins they need to.
Finally, if a person has a condition where blood clots (thrombi) are in the heart, this procedure could increase the risk of thromboembolic disease. This is when a blood clot breaks loose and travels through the bloodstream to block another vessel.
Equipment used for Electrophysiology Study and Ablation of Atrial Flutter
An electrophysiology (EP) lab, which is a specialized unit for heart tests, typically contains the following gear:
- A C-arm fluoroscopy system with a special table and an image enhancer. The C-arm fluoroscopy machine uses X-rays to show clear, real-time images of your heart.
- Heart stimulator and a system to collect and track the heart’s electrical activity data
- Introducer needles
- Different types of EP catheters for diagnosis, mapping, and ablation assays. Catheters are thin, flexible tubes inserted into the body to conduct the tests and procedures.
- An equipment interface
- An appliance to produce high-frequency electrical currents called a Radiofrequency energy generator
- An external defibrillator, a device that sends electric shocks to the heart to restore regular beating
- Temporary pacing system, a set-up used to regulate the heart’s rhythm
- Equipment to monitor blood pressure and other vital signs
- Intravenous systems to administer various fluids and essential medicines
- An emergency cart with suction, airways, tubes for breathing assistance, and urgent medications
For your safety and to handle any emergencies, we also recommend having the following back-up facilities and personnel:
- An anesthesia team, people who ensure you’re comfortable and pain-free during the procedures
- A unit with equipment and staff specially trained to care for patients with severe heart conditions
- Echocardiography, a test that uses sound waves to create detailed images of your heart
- Pericardiocentesis kit, tools to drain excess fluid from the sac around your heart if required
- Tools and experts available for Percutaneous coronary intervention, a non-surgical procedure to open narrowed arteries
- Cardiac surgery capabilities
Who is needed to perform Electrophysiology Study and Ablation of Atrial Flutter?
A doctor known as a cardiac electrophysiologist is typically the one who takes care of your heart’s electrical system. These doctors are experts in diagnosing and treating issues related to the heart’s rhythm. They work in a special place called a cardiac electrophysiology laboratory.
Assisting the electrophysiologist, we have a laboratory technician. This person’s job is to make sure all the equipment in the lab is working properly.
Nurses form part of this team too, providing you with care and support during the process. They check on your comfort and look after your overall well-being.
For more complex cases, an anesthesia team is also involved. They help to ensure that you do not feel pain during the procedure. Anesthesia is a special kind of medicine that makes you sleepy or completely unconscious during certain medical procedures.
Finally, we have the radiographers. They use equipment that takes images of your body, which can help the doctor to better understand and treat your heart problem.
Preparing for Electrophysiology Study and Ablation of Atrial Flutter
Before undergoing an AFL ablation procedure, where a doctor uses energy to destroy tiny areas in your heart that might be causing a heart rhythm problem, you will be fully briefed about the process. This includes understanding why the operation is necessary, the benefits it brings, the potential risks, and any other options available to you.
As part of your preparation for most heart rhythm testing processes, known as EP procedures, you’ll usually be asked to stop taking any anti-arrhythmia medications. This usually happens several days before the procedure, but there can sometimes be exceptions to this. Not all medications are the same, and some may need to be stopped longer in advance than others. EP studies are done inside the heart, so if you’re on medications to prevent blood clots, or certain drugs for controlling blood sugar levels, they might also need to be adjusted.
To prepare for surgery, you should not eat anything for at least 6 hours prior.
It’s also important to set up an intravenous line, often done before you arrive at the EP lab. Small, sticky patches called electrodes will be put on your skin to allow doctors to see your heart’s activity during the procedure via an ECG (a non-invasive test). Your heart will also be monitored using a blood pressure cuff or other ways if necessary. If you’re going to be given drugs to help you relax, your blood oxygen level will also be constantly checked. To use the defibrillator (a device to restore normal heartbeat) if needed, special pads may be placed on your body, also the skin electrode plate is required when ablation (destruction of problem-causing areas) is planned.
Different treatment centers may have different ways of giving medications before and during the EP procedure. At some centers, a combination of opiate (a painkiller), a benzodiazepine (a type of sedative), and an anti-nausea drug may be given, either as a premedication or as a slow conscious sedation. Or, general anesthesia, where you are put into a sleep-like state, might be used. This is particularly necessary if a lot of ablation is to be done, if there may be need for an external cardioversion (a procedure to restore normal heart rhythm), or if you are young or if the procedure is causing you a lot of stress.
How is Electrophysiology Study and Ablation of Atrial Flutter performed
The process of treating typical atrial flutter, a condition where the heart beats too fast, by destroying harmful electrical pathways in the heart is called Catheter Ablation. In this process, a complete line of blockage needs to be created within the normally occurring circuit of the heart. In atrial flutter, the electrical signals often move through a route called the Cavotricuspid Isthmus (CTI). Blocking this pathway through CTI is advantageous as the flutter wavefront cannot bypass it, creating a block is relatively short in length and it is safer than some other ablation targets.
To confirm the presence of CTI-dependent atrial flutter, a diagnostic test called an electrocardiogram (EKG) is usually done. This involves inserting a catheter with multiple electrodes into the right side of the heart and placing it at the CTI to study the heart’s electrical activity. Additional catheters are positioned in other parts of the heart as needed.
Once the diagnosis is confirmed, an ablation catheter is inserted into a vein in the leg and guided into the right side of the heart and through one of the heart valves, the tricuspid valve. From there, the catheter is used to create a series of lesions (regions of damaged tissue) along its path, starting from a point on the heart ventricle near the tricuspid valve, moving towards the back of the heart until the heart signal is no longer visible. These lesions form the line of block that interrupts the strange heart rhythm. It’s important that this line is uninterrupted since an incomplete block can lead to delayed conduction and potentially pro-arrhythmic conditions.
Verifying that the block has been successfully made is usually done using different techniques, but one common practice uses 2 catheters with multiple sensors. This approach allows doctors to observe changes in the sequence of heart activation during ablation. The block is confirmed when the catheter in the right atrium activates from the start to end while being paced from another area of the heart, the coronary sinus, and the last area activated is the closest to the line of the block.
In some cases, especially in those with a history of heart surgery, atrial flutters can occur that do not involve the CTI. Reentry, or the repeated circulation of electrical signals in the heart, can be caused by the suture line in the right atrium or by scar tissue from atrial dilation or, more rarely, heart muscle disease. The most likely pathways for reentry should be considered when performing ablation on these cases. Overall, the type of ablation technique used will be chosen based on the individual patient’s needs to provide the best outcome.
Possible Complications of Electrophysiology Study and Ablation of Atrial Flutter
The procedure known as Radiofrequency (RF) ablation, which is used to treat heart rhythm problems, has certain risks. It shares some risks with a standard heart electric system study – a type of test often done before the procedure. These potential issues are similar to those that can happen during any heart procedure. These include bleeding, blood clots, inflammation of a vein (phlebitis), infection, and accidental damage to the heart. However, these risks are significantly lower compared to a standard heart procedure, usually happening less than one percent of the time. This doesn’t take into account any harm from radiation exposure during the procedure.
There are more specific risks tied to RF ablation as well. For instance, there’s a chance that it could unintentionally cause complete heart block. This means that the electric signals from the top chambers of the heart can’t get to the bottom chambers resulting in a slow heart rate. There is also a potential for damage to the heart that could lead to a life-threatening condition called a cardiac tamponade. This typically happens when performing the ablation procedure near the heart’s chambers, the heart’s main vein, or an area of the heart called the right ventricle. However, these complications happen less than 2% of the time.
Some extremely rare complications can also occur, like developing new sources of rhythm disturbances, damaging heart valves resulting in leaky valves, blood clots traveling to the rest of the body when working inside the left chambers of the heart, narrowing of the veins that drain blood from the lungs, or creating narrow areas in the heart’s arteries. This is particularly concerning when treating areas near the right ventricular outflow tract, coronary sinus, or cardiac veins. However, the risk of severe, irreversible and life-threatening complications like death, heart attack, or stroke is less than 0.5%.
What Else Should I Know About Electrophysiology Study and Ablation of Atrial Flutter?
Radio Frequency (RF) ablation is generally safe and carries few risks. RF ablation targeted to treat arrhythmias, which are disorders where the heart beats irregularly, has become a top treatment option because of its high success rate. Arrhythmias can range from life-threatening to highly symptomatic, meaning they could drastically affect your daily life. In such cases, RF ablation can be effective, and the risks are often outweighed by the benefits.
RF ablation has become a standard treatment for most types of irregular heart rhythms. It works particularly well for treating a type of arrhythmia known as AFL or atrial flutter. Because of its success in treating this condition, RF ablation is seen as a good alternative to taking heart rhythm medications daily.
