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Marc Roelke, MD, Director
of Electrophysiology
Newark Beth Israel Medical Center
Saint Barnabas Medical Center |
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Roy Sauberman, MD, Electrophysiologist
Clara Maass Medical Center
Newark Beth Israel Medical Center
Saint Barnabas Medical Center |
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Nicholas Tullo, MD, Electrophysiologist
Saint Barnabas Medical Center |
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David Dobesh, MD, Electrophysiologist
Clara Maass Medical Center
Newark Beth Israel Medical Center
Saint Barnabas Medical Center |
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Steven Furer, MD, Electrophysiologist
Saint Barnabas Medical Center |
Cardiac resynchronization therapy,
also known as CRT and biventricular pacing, is
a new form of therapy for congestive heart failure.
In patients with congestive heart failure, the lower heart muscle becomes
weak and disorganized. This disorganization, which is also called dyssyncrony,
makes the heart pump less efficiently.
Conventional pacemakers pace from only one side of
the heart. In CRT pacing, an extra wire is added, and pacing occurs on
two sides of the heart, which allows the heart to beat more uniformly.
This increases its efficiency and improves clinical symptoms in approximately
70 percent of patients.
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Traditionally,
the patient for cardiac resynchronization therapy
(CRT) is someone with a weak heart muscle, moderate
to severe congestive heart failure, and an electrical
delay on electrocardiograms. This delay reflects
underlying dissyncrony, or disorganization, of
the heart muscle.
However, ongoing research trials are currently
looking at patients with less severe congestive
heart failure or with no congestive heart failure,
and without an electrical delay, to see if they
are candidates for biventricular pacing.
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Patients
may receive a pacemaker-only device to improve
their congestive heart failure symptoms. However,
many cardiac resynchronization therapy (CRT) candidates
with weak heart muscles are also at risk for sudden
death. These patients may receive a CRT device
with a built-in defibrillator, which would give
the patient a life-saving shock in the event of
a life-threatening arrhythmia.
The patient's electrophysiologist will make a recommendation about which device
is best for an individual patient.
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Sudden
cardiac death (SCD), also known as sudden cardiac
arrest, is death resulting in abrupt loss of heart
function. It is not the same as a heart attack.
Instead, it arises from an electrical disorder
of the heart which causes the heart to suddenly
stop pumping blood properly to the rest of the
body.
During sudden cardiac death, the electrical impulses
in the heart can become either too rapid (ventricular
tachycardia or ventricular fibrillation) or too
slow (asystole). If not properly treated, death
occurs within minutes. It is estimated that 450,000
sudden cardiac deaths will occur in the United
States this year, which equates to one death every
80 seconds.
Sudden cardiac death remains the number one cause
of preventable death in America today.
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People
with prior myocardial infarction (heart attack)
or congestive heart failure may be at increased
risk for sudden cardiac death. There are also
rare inherited conditions, such as long QT syndrome
and Brugada syndrome which can lead to sudden
cardiac death.
However, coronary artery disease remains the most
common heart condition associated with sudden cardiac
death, being present in up to 85 percent of sudden
cardiac arrest survivors.
In addition to blood pressure and cholesterol
levels, everyone should know their ejection fraction,
or EF. The ejection fraction is a measure of how
much blood pumps with each heart beat. The ejection
fraction can be accurately measured with a simple,
noninvasive echocardiogram or nuclear scan.
An abnormally low ejection fraction can be a sign
of heart disease and has been found to be the single
most important risk factor in predicting sudden
cardiac death. Studies have shown that patients
with reduced ejection fractions and either prior
myocardial infarction or congestive heart failure
may be at up to six- to nine-times greater risk
of sudden cardiac death as compared with the general
population.
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First
and foremost, preventing heart disease is the best
way of preventing sudden cardiac death:
- Maintain a heart-healthy lifestyle.
- Avoid high blood pressure, diabetes and high
cholesterol.
- Stop smoking and avoid secondhand smoke whenever
possible.
In an emergency, treating someone suffering from
sudden cardiac death may require “paddles” to
shock the heart back into normal rhythm.
There are additional tests and procedures that
are done in the hospital for people who have either
been resuscitated or who are felt to be at possible
risk for sudden cardiac death, including cardiac
electrophysiologic (EPS) testing and implantable
cardioverter defibrillator insertion.
Electrophysiologic (EPS) Testing
During electrophysiologic testing, thin small catheters
are inserted into the veins at the upper level
of the leg and advanced to the heart under X-ray
guidance. These catheters allow us to measure
the electrical system in the heart and allow
the doctor to diagnose symptomatic and potentially
life threatening slow and fast heart rhythms.
Cardioverter Defibrillators
When required, cardiac defibrillator insertion
can be performed. Cardiac defibrillators continuously
monitor the heart rhythm and automatically function
as pacemakers when the heart rate is too slow
while delivering life-saving shocks if a dangerously
fast heart rhythm is ever detected.
Cardiac defibrillators are 99 percent effective in
stopping all potential life-threatening arrhythmias
when they occur and have been found to be more effective
than medications in multiple trials.
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Fainting
is a very common clinical problem. It is also known
as syncope. Fainting occurs when a person loses
consciousness and slumps over in a chair or falls
to the floor.
Most people don’t realize that fainting
occurs because of a sudden drop in blood flow to
the brain. The brain requires a continuous flow
of blood in order to supply nutrients and oxygen
to the brain tissues. When blood flow to the brain
is suddenly reduced, a person can start to feel
lightheaded, hot and sweaty, vision can become
dark and he loses consciousness. Once the person
falls to the floor, blood flow is restored, the
brain wakes up again and the person regains consciousness,
usually within a minute or two.
The reason that blood flow to the brain stops
is usually related to blood pressure. In order
for blood to get from the heart to the brain, the
heart has to produce a certain amount of pressure
to force the blood uphill, against the force of
gravity. When blood pressure suddenly drops, blood
flow to the brain stops. The person can look very
pale because there is no blood getting to the skin
on their face either.
There may be many reasons for a drop in blood
pressure as the cause of fainting. Sometimes the
blood is in the wrong place at the wrong time or
there may not be enough blood in the body. Sometimes
it is due to a medication side effect.
The most common cause of fainting is due to an
abnormal reflex in the brain that causes a sudden,
inappropriate drop in blood pressure and sometimes
slows down the heart beat. This usually happens
in stressful circumstances, but not always. It
is referred to as vasovagal fainting or vasovagal
syncope.
Another cause of a sudden drop in blood pressure
is a heart rhythm disturbance. If the heart suddenly
slows down dramatically or stops for several seconds,
or if the heart suddenly starts beating very rapidly
because of an electrical disturbance known as an
arrhythmia, then the blood pressure can bottom
out. The person can faint very quickly, sometimes
without warning.
To diagnose the cause of the fainting, the doctor
has to be there when it happens and that is the challenging
part. We often have to do provocative testing that
brings on a fainting incident in order to uncover
its cause.
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Several
tests can be done to diagnose the cause of fainting.
- The most common test done in the doctor’s
office is an electrocardiogram
(ECG). An electrocardiogram
is simply an electrical recording of the heart
that can show evidence of a heart rhythm problem
or electrical disease of the heart.
- An echocardiogram is frequently
done. This is a sound wavy test that gives us
a picture of the beating heart to find out if
there is a heart muscle problem or a valvular
problem.
- Another common test is a tilt
table test for
diagnosing vasovagal syncope. A tilt table test
is also known as a standing test because the
patient is placed in a standing position with
a tilting table. Typically, the patient is placed
at an angle of about 60 to 70 degrees. Then we
monitor the blood pressure and heart rate over
the course of 20 to 30 minutes. For people with
vasovagal syncope, sometimes that alone will
cause a faint.
- If we suspect a heart rhythm abnormality, extended
monitoring is often done. A patient could wear
a heart monitor for up to two weeks.
- Often, we do a provocative test known as an
electrophysiology study. It is a simple safe
test that involves wires inserted into a vein
to reproduce a heart rhythm disturbance that
may be causing the fainting.
- For people who have infrequent episodes of fainting
with no obvious cause, we recommend an implantable
monitor. This is a small device that can last up
to three years. It is inserted under the skin in
a simple surgical procedure. The device records heart
rhythm disturbances that may result in syncope.
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Atrial
Fibbrillation is a disorder of the heart’s
natural electrical system. Instead of a nice
regular heart beat, individuals with atrial fibrillation
experience an irregular heart beat that may be
too fast or too slow, but is always irregular.
An irregular heart beat can result in a variety
of symptoms ranging from palpitation, or a sense
of fluttering in the chest to shortness of breath
with exertion or, possibly, fainting or dizzy
spells.
There are several ways to treat atrial fibrillation.
Sometimes medications are prescribed to slow down
the heart rate or keep the heart in a regular rhythm.
For some patients we may recommend that the patient
undergo a procedure called an invasive electrophysiology
study and an ablation which is designed to eliminate
the irregularity and maintain a regular heart rhythm.
Patients may also be advised to take blood thinners
to reduce the risk of stroke that can be associated
with atrial fibrillation.
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Not all
patients with atrial fibrillation will achieve
complete control of their symptoms with medications
alone. Often, patients are referred for an invasive
procedure called ablation. Using three-dimensional
computer modeling and a robotic navigation system,
the electrophysiologist can precisely deliver
cautery marks on the inside lining of the heart
to treat the abnormal signals that are responsible
for the irregular heart rhythms such as atrial
fibrillation.
Most patients will have complete control of their
symptoms after an ablation procedure. Some patients
may still need medications after the ablation and
others may require a second ablation procedure to
achieve complete control of their symptoms.
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Palpitations
are the sensation of feeling your heart beating.
It may be due to your normal heart beat; it may
be the sensation of a premature beat which begins
in the upper or the lower chamber of your heart;
or it may be due to a rapid heart beat. The cause
of your palpitations can be determined with a
test, called an electrocardiogram (ECG), which
can be performed in the doctor’s office.
You could also be sent home with a heart monitor
for 24 hours, or longer, to determine the cause
of your palpitations.
If tests show that the palpitations are merely
your normal heart beat, then simple reassurance
is all that is needed.
If the palpitations are due to a premature beat,
either from the upper or lower chamber of the heart,
reassurance may be all that is necessary. If the
patient has symptoms, then the doctor may consider
treatment with medication.
If the palpitations are due to tachycardia, we
will do more tests to find out if it is sinus tachycardia,
which is the normal condition of your heart beating
rapidly due to physiologic circumstances such as
exercise and stress.
If rapid heart beats are caused by super ventricular
tachycardia, or SVT, our electrophysiologists talk
to you about the treatment options which can include
behavior modification, such as limiting caffeine
and alcohol that can trigger SVT. Medications can
slow the heart down or suppress the arrhythmia
(irregular heart beat). There are also procedures
that can cure tachycardia.
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SVT,
or super ventricular tachycardia, is caused by
an abnormal circuit in the upper chamber of the
heart. The normal conduction of the heart starts
in the sinus node in the upper chamber and goes
to the AV node in the center of the heart and
travels down to the lower chamber in the ventricle.
There can be an irritable source in the upper
chamber called atrial tachycardia that can cause
fast heart rates. There is a reentrant circuit
in the center of the heart called AV nodal reentrant
tachycardia (AVNRT). And, there can be an
extra circuit connecting the upper chamber to the
lower chamber called AV reentrant tachycardia.
These extra circuits in the heart can cause rapid
heart beats. Depending on the duration and frequency
of the arrhythmia (irregular heart beat) people
can have symptoms of palpitations, shortness of
breath, dizziness and fatigue.
The first step is to determine what triggers your
arrhythmia and find out if you can eliminate the
trigger by changing your behavior. Common triggers
are alcohol, caffeine and stress. The next step is
to determine if medications will be effective on
your arrhythmia. Finally, there is a procedure called
catheter ablation that can cure arrhythmias.
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SVT can
be cured with a procedure called catheter ablation.
The procedure is performed in the cardiac cath
lab under general anesthesia by an electrophysiologist.
We start the procedure by placing IVs in the
right and left groin areas. We use the IVs to
pass small wires, called catheters, into the
heart. Once the catheters are in the heart, the
electrophysiologist induces the arrhythmia (or
irregular heart beat). Then we pinpoint its location
using a three-dimensional mapping system and
x-ray. Once we have targeted the location of
the abnormal electrical tissue, we use the catheter
to eliminate the arrhythmia.
Catheter ablation offers a very high success rate
and a low complication rate to cure a condition that
is often very symptomatic. A catheter ablation can
provide a cure for symptoms of palpitations and shortness
of breath. It allows patients to live without the
fear of a reoccurrence of their arrhythmia. It also
allows patient to stop taking medications which often
have side effects.
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