Supraventricular tachycardia (SVT) is one type of abnormally fast heartbeat, or heart rhythm. An abnormal heart rhythm is called an arrhythmia. An arrhythmia is caused by a problem in your heart’s electrical system. Electrical signals follow a certain path through the heart, which causes your heart to contract. During SVT, however, there are too many signals in part of the heart.
A tachycardia is an arrhythmia in which the heart beats (contracts) faster than 100 times per minute, rather than the normal rate of 60-100 beats per minute. SVT is a type of tachycardia that often occurs in the heart’s upper chambers (the atria). SVT can also occur just above the lower chambers (the ventricles), in tissue called the atrioventricular (A-V) node. Thus the tachycardia is called supraventricular tachycardia, or above (supra = above) the ventricles.
During SVT, the atria and ventricles often do not have enough time to fill with blood before the blood is pumped out of those chambers. This can cause symptoms.
There are many specific types of SVT. Most SVT begins and ends abruptly. However, the duration of SVT varies from seconds to hours or even longer.
One type of SVT is usually considered “normal”-sinus tachycardia.
Sinus tachycardia begins in the heart’s natural pacemaker, the sinoatrial node (also called the sinus node). During sinus tachycardia the sinoatrial node initiates electrical impulses more rapidly than usual. Sinus tachycardia is generally considered normal since it typically occurs during or after exercise, when your heart needs to beat faster than usual. However, sometimes sinus tachycardia happens in response to fever, too much caffeine or alcohol, or an overactive thyroid gland (hyperthyroidism). Sinus tachycardia itself is not treated. But if this
arrhythmia happens as a result of fever, for example, the underlying cause may be treated.
Generally, a problem with the heart’s electrical system causes supraventricular tachycardia (SVT). Either too many electrical signals are produced in the sinoatrial node, or they do not travel down the proper pathways in the heart. If a signal travels down an extra electrical pathway, it can sometimes circle repeatedly on the extra pathway, causing symptoms. To learn more about your heart’s electrical system, go to the Heart & Blood Vessel Basics section.
However, the underlying cause of SVT varies from person to person. The abnormal electrical signals can result from:
In some cases SVT can lead to rapid arrhythmias in the ventricles- which can be more serious. And in some cases SVT can lead to cardiomyopathy.
Symptoms of supraventricular tachycardia (SVT) vary. Some people notice their heart fluttering or have palpitations (a feeling that your heart is racing or that your heartbeat is irregular). Other people have chest pain, fatigue, weakness, sweating, dizziness, lightheadedness, fainting, an upset stomach, or a decreased appetite. Although SVT is usually not life threatening, the symptoms can be severe.
Your doctor might begin by checking your blood pressure, since low blood pressure can be a sign of a supraventricular tachycardia (SVT). Then your doctor may suggest one or more of the tests listed below. The test results can also help your doctor choose the best treatment(s) for you.
In some cases you may be sent to specialists for diagnosis and testing- and sometimes for treatment. To learn more, go to the Your Treatment Team section.
An echocardiogram (also called an echo) is a three-dimensional, moving image of your heart. An echo uses Doppler ultrasound technology. It is similar to the ultrasound test done on pregnant women. The echo machine emits sound waves at a frequency that people can’t hear. The waves pass over the chest and through the heart. The waves reflect or “echo” off of the heart, showing:
What can I expect?
When you have an echocardiogram, you undress from the waist up, put on a hospital gown, and lie on an exam table. The technician spreads gel on your chest and side to help transmit the sound waves. The technician then moves a pen-like instrument (called a transducer) around on your chest or side. The transducer records the echoes of the sound waves. At the same time, a moving picture of your heart is shown on a special monitor. You may be asked to lie on your back or your side during different parts of the test. You may also be asked to hold your breath briefly so that the technician can get a good image of your heart. An echo is a painless test. You feel only light pressure on your skin as the transducer moves back and forth.
An electrocardiogram (ECG or EKG) reveals how your heart’s electrical system is working. The ECG senses and records your heartbeats, or heart rhythms. The results are printed on a strip of paper. An ECG can also help your doctor
diagnose whether:
In all, there are three kinds of tests that record your heart’s electrical activity, each for a different period of time:
The peaks on an electrocardiogram (ECG) strip are called waves. Together, all the peaks and valleys give your doctor important information about how your heart is working:
When you have an electrocardiogram (ECG) you undress from the waist up, put on a hospital gown, and lie on an exam table. As many as 12 small patches called electrodes are placed on your chest, neck, arms, and legs. The electrodes, which connect to wires on the ECG machine, sense the heart’s electrical signals. The machine then traces your heart’s rhythm on a strip of graph paper.
An electrophysiology (EP) study is a test of your heart’s electrical system. While an
electrocardiogram (ECG) gives an overview of your heart’s electrical system, the EP study gives a more in-depth view. The test helps find out details about abnormal heart rhythms, called arrhythmias. The EP study can reveal:
The EP study begins when one or more leads are inserted into a blood vessel, usually in the groin. The doctor gently “steers” the leads toward your heart. Once in place, the leads sense your heart’s electrical activity. One special lead also delivers electrical signals to your heart to trigger an arrhythmia. That’s to help find out how easily your heart can produce arrhythmias on its own.
During the EP study, your doctor closely monitors your heartbeats. If an arrhythmia occurs, the doctor treats you with: Medications given through the intravenous (IV) line in your arm or hand Electrical signals delivered to the outside of your chest through patches
In some cases, ablation (a form of treatment) is done at the same time as your EP study. (To learn about ablation, go to the Procedures part of the Medications & Procedures section.) Or your doctor can suggest other types of treatment after the EP study.
What can I expect?
Your test will be performed in a “cath lab.”You undress, put on a hospital gown or sheet, and lie on an exam table. An intravenous (IV) line put into your arm delivers fluids and medications during the test. The medication makes you groggy, but not unconscious. Patches called electrodes are put on your chest. The electrodes monitor your heart’s electrical signals during the test. A blood pressure cuff on your arm also regularly takes your blood pressure.
The doctor makes a small incision (usually in the groin) for the catheter. The groin area will be numbed so you shouldn’t feel pain, but you may feel some pressure as the catheter is inserted. If the doctor delivers electrical signals to your heart, you might feel your heart racing or pounding. You won’t be fully asleep, so during the test your doctor or nurse might ask you questions.
Afterwards you may be in the hospital overnight, but most people have a fairly rapid recovery.
An event recorder is a small device that tracks your heart’s electrical activity. An event recorder monitors your heart’s electrical activity for an extended period of time- usually from a week to a month or more. The recorder is always on, but it saves your heart rhythms into its memory only when you push a button. Many recorders save recordings of your heart rhythms for 30-60 seconds both before and after you push the button.
An event recorder can help your doctor find out if you have abnormal heart rhythms, or arrhythmias. Arrhythmias might happen rarely, yet it is still important for your doctor to know about them and to treat them.
In all, there are three kinds of tests that record your heart’s electrical activity, each for a different period of time:
When the heart rhythms from any of these three tests are printed out, they all look the same: the electrical signals look like peaks and valleys. A doctor may suggest an event recorder when you have symptoms only once a week or once a month.
Two sticky patches called electrodes are placed on your chest. The electrodes connect to wires on the event recorder. The electrodes sense your heart rhythms, while the event recorder records and stores the rhythms. Your doctor or nurse will show you how to take the electrodes off for bathing and then put them back on. The event recording device itself is the size of a small portable tape recorder. It fits easily on a belt or in a pocket.
You press the button when you feel symptoms. This causes the device to store a small segment of the recordings. Make sure your family and friends know how to start the recorder too. In case you have symptoms, they can help you press the recorder button. Any stored recordings can be sent to your doctor’s office, clinic, or hospital. The staff there will let you know if you need to follow up with your doctor.
You should be able to do most or all of your daily activities at home and work while using the event recorder. You won’t feel anything while the event recorder is tracking your heart rhythms. However, sometimes your skin can become irritated from the sticky patches.
Holter monitoring uses a small recording device called a Holter monitor. The monitor tracks and records your heart’s electrical activity, usually for 24-48 hours.
Holter monitoring can help your doctor find out if you have abnormal heart rhythms, or arrhythmias. Arrhythmias might happen rarely, yet it is still important for your doctor to know about them and to treat them.
In all, there are three kinds of tests that record your heart’s electrical activity, each for a different period of time:
When the heart rhythms from any of these three tests are printed out, they all look the same: the electrical signals look like peaks and valleys. A doctor may suggest Holter monitoring when you have symptoms at least once every day or two.
Your doctor may ask you to write down any symptoms you have during the test. Symptoms might include faintness, dizziness, or fluttering in the chest.
You should note the time and how long the symptoms last. Your doctor might also ask you to write down when you exercise, take medications, or get upset. This can help your doctor see if there is a connection between your heart rhythms and your symptoms or activities.
As many as seven sticky patches called electrodes are placed on your chest. The electrodes connect to wires on the Holter monitor. The electrodes sense your heart rhythms, while the monitor records and stores the rhythms. Since the electrodes cannot get wet, you should shower or bathe before you begin the Holter monitoring, and not at all during the testing. The Holter monitor device itself is the size of a small portable tape recorder. It fits easily on a belt or can be worn on a shoulder strap.
You should be able to do most or all of your daily activities at home and work while using the Holter monitor. You won’t feel anything while the Holter monitor is tracking your heart rhythms. After 24-48 hours, you return the monitor. A technician examines the recordings, notes whether you had any arrhythmias, and prepares a report for your doctor.
Your treatment depends on your test results. Your doctor may recommend one or more of these medications or procedures.
Medications
If you have a heart or blood vessel condition, you might want to know more about some of the medications you take. The information in this section describes some medications commonly prescribed for heart or blood vessel conditions. It also includes some tips to help you take your medications as ordered.
Make sure you tell your doctor-or any new doctor who prescribes medication for you-about all the medications and supplements you take. Your doctor can then help make sure you get the most benefit from your medications. Telling your doctor this information also helps avoid harmful interactions between medications.
You may also want to discuss these topics with your doctor or nurse each time you get a new medication:
In some cases, your heart needs several months to adjust to new medications. So you may not notice any improvement right away. It also may take time for your doctor to determine the correct dosage.
Blood tests are sometimes necessary for people who take heart medications. The blood tests help your doctor determine the correct dosage- and therefore help avoid harmful side effects.
Never stop taking your medication or change the dosage on your own because you don’t believe you need it anymore, don’t think it’s working properly, or feel fine without it.
Be sure to talk to your doctor or nurse if you have:
And don’t hesitate to ask your pharmacist if you have questions about how and when to take your medications.
Antiarrhythmics affect the electrical system in your heart. You can understand the purpose of antiarrhythmics by looking at the root words of the term. Anti = counter or against; arrhythmia = an abnormal heartbeat or heart rhythm.
All medications are approved by the Food and Drug Administration (FDA) for a specific patient group or condition. Only your doctor knows which medications are appropriate for you.
Sometimes other categories of medications-beta blockers and calcium channel blockers-are used to help prevent arrhythmias.
Antiarrhythmic drugs work in different ways to change the electrical activity in your heart. Different drugs are used because the source of the arrhythmia can come from different places in the heart.
Taking antiarrhythmics can:
Beta blockers get their name because they “block” the effects of substances like adrenaline on your body’s “beta receptors.”
All medications are approved by the Food and Drug Administration (FDA) for a specific patient group or condition. Only your doctor knows which medications are appropriate for you.
To treat high blood pressure
To slow fast arrhythmias (abnormal heartbeats, or heart rhythms)
To prevent angina (chest pain due to blocked blood flow to parts of the heart) To prevent long-term damage after a heart attack
To treat heart failure and related conditions, such as low ejection fraction (EF)
These medications block activity of your sympathetic nervous system. The sympathetic nervous system reacts when you are stressed or when you have certain health conditions. When your system responds, your heart beats faster and with more force. Your blood pressure also goes up.
Beta blockers block signals from the sympathetic nervous system. This slows your heart rate and keeps your blood vessels from narrowing. These two actions can result in:
Beta blockers block signals from the sympathetic nervous system. This slows your heart rate and keeps your blood vessels from narrowing. These two actions can result in:
The word “inotrope” refers to the strength of the heart muscle’s pumping action, or contractions.
All medications are approved by the Food and Drug Administration (FDA) for a specific patient group or condition. Only your doctor knows which medications are appropriate for you.
The term “inotrope” describes the strength and force of the heartbeat. Taking inotropic medications can:
Calcium channel blockers help relax the heart muscle and blood vessels.
All medications are approved by the Food and Drug Administration FDA for a specific patient group or condition. Only your doctor knows which medications are appropriate for you.
Calcium channel blockers prevent calcium from entering parts of the cells in blood vessels. When calcium is blocked from entering these cells, it relaxes the blood vessels and the heart. As a result, calcium channel blockers:
Ablation destroys (ablates) targeted portions of the heart muscle. Your doctor carefully chooses portions of the heart muscle to treat. Then your doctor delivers small amounts of energy to these selected areas. This creates lesions (helpful scars) on the heart muscle.
Ablation can be done as a type of surgery or as a procedure using a catheter. A catheter is a flexible tube that is inserted into a blood vessel.
Your doctor will decide whether a catheter ablation or a surgical ablation is right for you. This section describes both catheter and surgical ablation.
Other names for ablation: cardiac ablation, catheter ablation, cryoablation, microwave ablation, radiofrequency ablation, surgical ablation.
Catheter ablation does not require incisions in the chest. This type of ablation begins with a catheterization. During a catheterization, a small flexible tube called a catheter is inserted through a blood vessel in your groin (or sometimes in your neck). Your doctor gently “steers” the catheter into your heart. Your doctor can see where the catheters are going by watching a video screen with real-time images, or moving x-rays, called fluoroscopy.
The electrode at the tip of the catheter senses your heart’s electrical signals and takes electrical measurements. Your doctor tests your heart and then “ablates”
sections of the muscle tissue using the catheter. Catheter ablation can be done using:
In some cases, when ablation is done in certain parts of the heart, you may need a pacemaker afterwards.
Minimally invasive surgical ablation requires six small incisions in the sides of your chest. These incisions (% to % inches in size) are much smaller than the incisions needed for traditional open-heart surgery. Through these incisions, your doctor inserts a tiny camera to view the heart. Your doctor then inserts small instruments to test your heart and ablate the tissue as needed.
Open-heart surgical ablation requires a longer incision down the middle of the chest, through the breastbone (sternum). This type of ablation is usually done if you also need to have another type of treatment, such as a valve replacement or bypass surgery.
With either type of surgical ablation, your doctor ablates sections of the heart muscle tissue by delivering energy to the heart and creating lesions (scars). Surgical ablation can be done using:
Usually you are told not to eat or drink anything for a number of hours beforehand. Catheter ablation is performed in a “cath lab.” And surgical ablation is performed in an operating room. You lie on an exam table and an intravenous
(IV) line is put into your arm. The IV delivers fluids and medications.
A few details about each type of procedure or surgery is explained as follows.
Catheter ablation
The medications in the IV make you groggy, but not unconscious. To insert the catheter, the doctor makes a small incision in the groin (or the neck), but not in the chest. The area will be numbed so you shouldn’t feel pain, but you may feel some pressure as the catheter is inserted. During ablation your doctor or nurse might ask you questions. Afterwards you may be in the hospital overnight.
Minimally invasive surgical ablation
During a surgical ablation, you will receive medication that makes you unconscious. You will not be aware of the incisions made in the side of your chest, or of the ablation itself. After surgery you will probably be in the hospital for one to two days.
During a surgical ablation, you will receive medication that makes you unconscious. You will not be aware of the incision in your chest, or of the ablation itself. After surgery you may spend several days in the hospital. You may have pain at the incision site for several weeks. Your recovery will depend in part on the other heart surgery you likely had done at the same time as the ablation.
Atrial Fibrillation: Fuster V, Ryden LE, Asinger RW, et al. ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation: executive summary, a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences. Circulation. 2001;104:2118-2150.
Supraventricular Tachycardia : Blomstrom-Lundqvist C, Schein man MM, Aliot EM, et al. ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias- executive summary, a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines. J Am Coll Cardio/. 2003;42:1493-1531.
Ventricular Tachycardia: Schein man M, Calkins H, Gillette P, et al. NASPE Policy Statement on Catheter Ablation: personnel, policy, procedures, and therapeutic recommendations. PACE.
2003;26 :789-799.
Both cardioversion and defibrillation deliver an electrical shock to the heart. The shock can restore a normal heartbeat. Both types of treatment are used in people who have abnormal heartbeats or heart rhythms, called arrhythmias.
Cardioversion is a lower-energy shock delivered to your heart. Cardioversion can stop a very fast arrhythmia.
Defibrillation is a high-energy shock delivered to your heart. You need this treatment if you have a very fast and chaotic arrhythmia in your heart’s lower chambers (ventricles). For instance, defibrillation is needed for arrhythmias like ventricular tachycardia (VT) or ventricular fibrillation (VF). Defibrillation is the only effective treatment for VF. If VF is not treated, it can quickly lead to sudden cardiac death (SCD).
The concept behind cardioversion and defibrillation is the same. Both types of treatment stop all electrical activity in the heart for a second. When the heart resumes beating, its electrical system often works correctly once again. If you want to learn more about your heart’s electrical system, go to the Heart & Blood Vessel Basics section.
Internal cardioversion is delivered by an implanted device. If you have an implantable cardioverter defibrillator (ICD), it can sense a fast arrhythmia. The ICD then delivers a low-energy shock. The shock can stop the arrhythmias and restore a normal heartbeat.
External cardioversion is delivered by an external device. This is a scheduled treatment often used to treat fast arrhythmias in the heart’s upper chambers (atria).
Internal defibrillation is delivered by an ICD device. When the device senses an arrhythmia like ventricular fibrillation (VF), the ICD delivers a lifesaving shock.
External defibrillation is delivered by an external defibrillator. You’ve probably seen external defibrillators on TV medical dramas. The machine is connected to two paddles that deliver a shock to the outside of the chest. Because brain damage starts to occur within 4-6 minutes after VF begins, defibrillation should be done as soon as possible. Because fast arrhythmias can be so dangerous, some public buildings and airplanes now have external defibrillators.
Internal cardioversion or defibrillation from an implanted device can come as a surprise if you aren’t having symptoms. You will feel cardioversion but it may not be painful. On the other hand, a high-energy shock from defibrillation can be painful. But an arrhythmia like VF will rarely stop on its own-it must be treated for the person to survive. So defibrillation is typically a lifesaving therapy.
External cardioversion is usually a scheduled treatment in your doctor’s office. Your doctor may recommend it if your atrial arrhythmias do not respond to medications. You undress and put on a hospital gown or sheet. You lie on an exam table and an intravenous (IV) line is put into your arm. The IV delivers fluids and medications during the short procedure. The medication makes you groggy, but not unconscious. Your doctor puts patches called electrodes on your chest. The electrodes connect to wires on the device. The device delivers the shock. Most people say they have little or no pain afterwards.
External defibrillation is done in an emergency situation. Someone who receives this treatment is typically unconscious. After the shock is delivered, there may be some pain and skin irritation on the chest (from the paddles).
A pacemaker is a small implanted device that treats abnormal heart rhythms called arrhythmias. Specifically, a pacemaker treats slow arrhythmias called bradycardia. A pacemaker can usually eliminate symptoms like shortness of breath, fatigue, and dizziness caused by bradycardia.
Arrhythmias result from a problem in your heart’s electrical system. Electrical signals follow a certain path throughout the heart. It is the movement of these signals that causes your heart to contract. During bradycardia, however, too few signals flow through the heart. To learn more about your heart’s electrical system, go to the Heart & Blood Vessel Basics section.
A pacemaker restores your heart to a normal rhythm. The pacemaker can also adjust to your body’s needs. This is because the device has sensors that can detect:
Perhaps your heart does a good job of regulating your heart rhythm most of the time. A pacemaker is used as backup treatment only when your heart needs it.
In other cases, a person’s heart can no longer create its own electrical signals, or send them down the proper pathways. For example, sometimes aging, or an ablation procedure in certain parts of the heart, can make pacemaker therapy necessary. In such cases the pacemaker might deliver continual treatment, in order to cause each heartbeat.
The pacemaker delivers electrical signals to the heart. The device does this by sending tiny amounts of electrical energy (too small to feel) to either the top or the bottom chambers of the heart, or to both.
A device implant is a procedure that uses local numbing. General anesthesia usually is not needed.
An implanted device needs to be checked regularly to review information that is stored in the device and to monitor settings.
A pacemaker system has two parts.
Device-the device is quite small and easily fits in the palm of your hand. It contains small computerized parts that run on a battery.
Leads-the leads are thin, insulated wires that connect the device to your heart. The leads carry electrical signals back and forth between your heart and your device.
Your doctor inserts the leads through a small incision, usually near your collarbone. Your doctor gently steers the leads through your blood vessels and into your heart. Your doctor can see where the leads are going by watching a video screen with real-time, moving x-rays called fluoroscopy.
The doctor connects the leads to the device and then tests to make sure both work together deliver treatment. Your doctor then places the device just underneath your skin and stitches the incision closed.
Usually you are told not to eat or drink anything for a number of hours before the procedure. You undress and put on a hospital gown or sheet. Your procedure will be performed in a “cath lab.” You lie on an exam table and an intravenous (IV) line is put into your arm. The IV delivers fluids and medications during the procedure. The medication makes you groggy, but not unconscious.
The doctor makes a small incision near your collarbone to insert the leads. The area will be numbed so you shouldn’t feel pain, but you may feel some pressure as the leads are inserted. You may be in the hospital overnight, and there may be tenderness at the incision site. Most people have a fairly quick recovery.
Our knowledgeable and courteous staff will help set up a consultation for you, schedule surgical procedures, discuss your insurance, and answer any questions you may have.
