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HEALTH CONDITIONS
SUPRAVENTRICULAR TACHYCARDIA
What is it?
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
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arrhythmia happens as a result of fever, for example, the underlying cause may
be treated.
What is the cause?
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:
 Bacterial pneumonia
 Chronic obstructive pulmonary disease (COPD)
 Congenital heart problem (a problem present from birth)
 Coronary artery disease (CAD) (not enough blood supply in heart)
 Damage or death of some heart tissue, which can result from a heart attack
 Diabetes
 Heart failure
 Valve disease
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.
What are the symptoms?
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.
What tests could I have?
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.
Echocardiogram
Electrocardiogram (ECG or EKG)
Electrophysiology (EP) Study
Event Recorder
Holter Monitoring
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Echocardiogram
What is an echocardiogram?
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 the heart, showing:
• The shape and size of your heart
• How well the heart valves are working
• How well the heart chambers are contracting
• The ejection fraction (EF), or how much blood your heart pumps with each
beat
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.
Electrocardiogram (ECG or EKG)
What is an ECG?
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:
• You have arrhythmias
• Your heart medication is effective
• Blocked coronary arteries (in the heart) are cutting off blood and oxygen to
your heart muscle
• Your blocked coronary arteries have caused a heart attack
In all, there are three kinds of tests that record your heart's electrical activity,
each for a different period of time:
• Electrocardiogram (ECG)—done in the doctor's office. It records your heart
rhythms for a few seconds.
• Holter monitoring—records and stores (in its memory) all of your heart
rhythms for 24-48 hours.
• Event recorder—constantly records your heart rhythms. But it stores the
rhythms (in its memory) only when you push a button.
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The P-Q-R-S-T waves in a series reflect one heart beat.
What are the parts of an ECG strip?
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:
• The P-wave shows your heart's upper chambers (atria) contracting
• The QRS complex shows your heart's lower chambers (ventricles) contracting
• The T-wave shows your heart's ventricles relaxing
What can I expect?
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.
Electrophysiology (EP) Study
What is an EP study?
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:
• If you have an arrhythmia
• The cause of the arrhythmia
• Where the arrhythmia begins in the heart
• If you are at risk for sudden cardiac arrest (SC)
• The best treatment for an arrhythmia
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?
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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.
Event Recorder
What is an event recorder?
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:
• Electrocardiogram (ECG)—done in the doctor's office. It records your heart
rhythms for a few seconds.
• Holter monitoring—records and stores (in its memory) all of your heart
rhythms for 24-48 hours.
• Event recorder—constantly records your heart rhythms. But it stores the
rhythms (in its memory) only when you push a button.
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.
What can I expect?
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
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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
What is Holter monitoring?
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:
• Electrocardiogram (ECG)—done in the doctor's office. It records your heart
rhythms for a few seconds.
• Holter monitoring—records and stores (in its memory) all of your heart
rhythms for 24-48 hours.
• Event recorder—constantly tracks your heart rhythms. But it stores the
rhythms (in its memory) only when you push the button.
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.
What can I expect?
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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, however, your skin may become irritated from the
sticky patches.. 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.
What are the treatment options?
Your treatment depends on your test results. Your doctor may recommend one
or more of these medications or procedures.
Medications
Antiarrhythmics
Beta Blockers
Calcium Channel Blockers
Inotropes
Procedures
Ablation
Cardioversion & Defibrillation
Pacemaker Implant
MEDICATIONS
Tips for Taking Heart 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 dietary 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 and supplements.
You may also want to discuss these topics with your doctor or nurse each time
you get a new medication:
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•
•
•
The reason you're taking the medication, its expected benefits, and its
possible side effects
How and when to take your medications
If you take other medicines, vitamins, supplements, or other over-the-counter
products
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:
• Questions about how your medications work
• Unpleasant side effects
• Trouble remembering to take your pills
• Trouble paying for your medications
• Other factors that prevent you from taking your medications as needed
• Questions about taking any of your medications
And don't hesitate to ask your pharmacist if you have questions about how and
when to take your medications.
Antiarrhythmics
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.
Some generic (and Brand) names
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.
amiodarone (Cordarone, Pacerone)
disopyramide (Norpace)
dofetilide (Tikosyn)
flecainide (Tambocor)
procainamide (Procanbid)
propafenone (Rythmol)
quinidine (Quinaglute)
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Sometimes other categories of medications—beta blockers and calcium channel
blockers—are used to help prevent arrhythmias.
What they're used for
To prevent and treat tachyarrhythmias (abnormally fast heartbeats, or heart
rhythms)
To restore normal heart rhythms
How they work
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:
Restore a normal heart rhythm
Prevent abnormally fast rhythms.
Beta Blockers
Beta blockers get their name because they "block" the effects of substances like
adrenaline on your body's "beta receptors."
Some generic (and brand) names
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.
acebutolol (Sectral)
atenolol (Tenormin)
betaxolol (Kerlone)
bisoprolol (Zebeta)
carvedilol (Coreg)
labetalol (Trandate)
metoprolol (Lopressor, Toprol)
nadolol (Corgard)
penbutolol (Levatol)
pindolol (Visken)
propranolol (Inderal)
sotalol (Betapace, Sorine)
timolol (Blocadren)
What they're used for
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)
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How they work
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:
• Lower heart rate
• Lower blood pressure
• Less angina (chest pain related to the heart)
• Fewer arrhythmias (abnormal heartbeats, or heart rhythms)
Inotropes
The word "inotrope" refers to the strength of the heart muscle's pumping action,
or contractions.
Some generic (and Brand) names
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.
digoxin (Digitek, Lanoxicaps, Lanoxin)
What they're used for
To improve symptoms of heart failure and related conditions, such as low
ejection fraction (EF)
To slow the heart rate in response to atrial fibrillation (fast rhythm in the heart's
upper chambers)
How they work
The term "inotrope" describes the strength and force of the heartbeat. Taking
inotropic medications can:
Make the heart beat more strongly and efficiently
Help slow and control the heart rate for certain arrhythmias
Calcium Channel Blockers
Calcium channel blockers help relax the heart muscle and blood vessels.
Some generic (and Brand) names
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.
amlodipine (Norvasc)
diltiazem (Cardizem, Dilacor, Diltia, Tiazac, Taztia)
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felodipine (Plendil)
isradipine (DynaCirc)
nicardipine (Cardene)
nifedipine (Adalat, Procardia)
verapamil (Calan, Covera, Isoptin, Verelan)
What they're used for
To treat high blood pressure
To treat angina (chest pain) which can result from atherosclerosis (blocked blood
vessels) and coronary artery disease (CAD)
To treat some arrhythmias (abnormal heartbeats, or heart rhythms)—usually fast
arrhythmias
How they work
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:
• Decrease the work of the heart by allowing more blood and oxygen to flow to
the heart muscle
• Lower the heart rate
• Lower blood pressure
PROCEDURES
Ablation
What is ablation?
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.
How is it done?
Catheter 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
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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:
• Intense cold, called cryoablation
• High-frequency energy, called radiofrequency ablation
In some cases, when ablation is done in certain parts of the heart, you may need
a pacemaker afterwards.
Surgical ablation
Minimally invasive surgical ablation requires six small incisions in the sides of
your chest. These incisions (½ to ¾ 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:
• Intense cold, called cryoablation
• Microwave energy, called microwave ablation
• High-frequency energy, called radiofrequency ablation
• Ultrasound energy
• Laser energy
What can I expect?
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
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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.
Open-heart surgical ablation
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.
Ablation References
ACCF/AHA/HRS focused update on the management of patients with atrial fibrillation (updating
the 2006 guideline): a report of the American College of Cardiology Foundation/American Heart
Association Task Force on Practice Guidelines. Heart Rhythm 2011;8:157–176.
Supraventricular Tachycardia : Blomstrom-Lundqvist C, Scheinman 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 Cardiol. 2003;42:1493-1531.
Ventricular Tachycardia: Scheinman M, Calkins H, Gillette P, et al. NASPE Policy Statement on
Catheter Ablation: personnel, policy, procedures, and therapeutic recommendations. PACE.
2003;26:789-799.
Cardioversion & Defibrillation
What is cardioversion & defibrillation?
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).
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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.
How is cardioversion or defibrillation done?
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.
What can I expect?
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).
Pacemaker Implant
What is a pacemaker?
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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:
• When you rest and need a slow heart rate
• When you exercise and need a faster heart rate
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.
How is the implant procedure done?
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
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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.
What can I expect?
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.
Important Safety Information
Medications, procedures and tests can have some risks and possible side effects. Results may vary
from patient to patient. This information is not meant to replace advice from your doctor. Be sure to talk
to your doctor about these risks and possible side effects.
Cardiac resynchronization therapy pacemakers (CRT-P) and defibrillators (CRT-D) are used to treat
heart failure patients who have symptoms despite the best available drug therapy. These patients also
have an electrical condition in which the lower chambers of the heart contract in an uncoordinated way
and a mechanical condition in which the heart pumps less blood than normal. CRT-Ps and CRT-Ds are
not for everyone including people with separate implantable cardioverter-defibrillators (CRT-P only) or
certain steroid allergies. Procedure risks include infection, tissue damage, and kidney failure. In some
cases, the device may be unable to respond to your heart rhythm (CRT-P only) or may be unable to
respond to irregular heartbeats or may deliver inappropriate shocks (CRT-D only). In rare cases severe
complications or device failure can occur. Electrical or magnetic fields can affect the device. Only your
doctor knows what is right for you.
Boston Scientific is a trademark and HEARTISTRY is a service mark of Boston Scientific Corporation.
All other brand names mentioned are used for identification purposes only and are trademarks of their respective owners.
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