How Are Arrhythmias Treated?
There are dozens of arrhythmias
that differ vastly in their symptoms severity,
and available treatments. For each arrhythmia, frequently, there can be more
than one therapeutic options. These factors can result in a bewildering
array of treatment choices and professional opinions, creating a great deal of confusion for patients.
especial true for patients who have sought multiple "second opinion"
consultations. It is not unusual for these patients to become
confused and more indecisive after each additional second opinion
consultations he or she went to.
It is often said that medicine
is an "art." In other words, diagnosis and therapy for many
medical conditions, including arrhythmias, are not always "black and
white." There are "judgment calls" and variation in
professional opinions. Therefore, it is probably not possible
that any two physicians would give identical opinions for any
medical condition, except for a very select few conditions where it
is clearly a "life and death" situation. For many conditions
where treatments are elective or semi-elective, there can be many
equally viable treatment options. The choice is often made by
the patient in conjunction with their physicians.
This section on the treatments of arrhythmia is,
therefore, not meant to provide an answer to
every arrhythmia, but rather to discuss the general principles of treating
arrhythmias. Certain myths in
treating arrhythmias are also discussed. This is then followed by detailed
discussion on specific treatment procedures in Cardiac
General Principles of Treating Arrhythmias:
Frequently, there can be as many different opinions
regarding treatment options for any given arrhythmia as there are
physicians willing to provide them. However, there are some
general principles and guidelines that most physicians do agree on.
1) Primum non nocere.
This Latin phrase translates to "First, do no harm,"
which is the first and foremost principle that all physicians agree
on and adhere to. With whatever treatment recommendation a
physician prescribes, either medical or surgical, the patient should
not be harmed as a result. Medical treatments are meant to
help, not worsen, the medical condition. However, one should
keep in mind that there are practically no treatments that are
completely harmless. There are risks in every medication
and every surgery. (If someone tells you that a particular
medication has "absolutely no side effect," he or she is not being
truthful about it.) The important principle is that if the
treatment should not be worse than the disease itself. This is
where "risk/benefit analysis" comes in.
2) Risk/Benefit Analysis.
This is a basic principle that applies not only to
Cardiac Electrophysiology, but practically in every aspect of
Medicine. The rule is very simple. Whenever one
considers a treatment option, the benefits of the treatment must
outweigh the potential risks (side effects, complications, etc) of
the treatment. A very common example is chemotherapy for
cancers. This therapy is well known to be "toxic."
Without the toxicity, it simply can not kill the cancer cells.
However, there are very few chemotherapies that are so specific as
to kill only the cancer cells, not healthy normal cells. This
"collateral damage" is why patients frequently lose their hair and
have dangerously low white blood cells during chemotherapy.
But most patients and physicians will happily embrace chemotherapy
because without it patient may die. In other word, one is
willing to accept a "toxic" therapy because the disease is worse
than the treatment. In the case where the treatment is worse
than the disease, the treatment would not be a good one.
As the above example shows, the more serious a medical condition is, the more one would
be willing to accept a treatment option with potentially higher
risks. Unfortunately, as it turns out, the risk of treatments
for more serious conditions usually are higher compared to those for
less serious conditions. An example
would be Tylenol for headache and chemotherapy for leukemia.
Again, one would accept a treatment with potentially higher risk if
the potential benefit is higher.
This general principle applies to Cardiac
Electrophysiology as well. An arrhythmia such as
carries a completely benign prognosis. Patients usually have
no symptoms or have minimal symptoms. Therefore, the threshold
for treating these patients with any medications that have serious side effects would be very high.
Most patients would be treated with milder medications, which may be
less effective, but less risky. Patients would have to be
severely symptomatic in order to take on the risk of taking the more
effective, but potentially more toxic, medications. On the other hand, an arrhythmia like
ventricular tachycardia is life-threatening and carries an ominous prognosis.
Therefore, one would be willing to accept more aggressive treatment
options, even those with potentially higher risks, because the ultimate
benefits outweigh the risks.
Similar to the example of Tylenol versus
chemotherapy, the more effective a treatment is in Cardiac
Electrophysiology, the more potential risk. This is easy to
understand. An extreme example would be a patient with an
arrhythmia who chooses to treat himself with nothing. This
"nothing" will have less side effect than a medication like
amiodarone, but would be far less effective in controlling the
The above paragraphs discussed how we choose
treatment options based on risk/benefit analysis. The
following section discusses why we treat any medical condition. There are only two
reasons to treat a patient, for any ailment, for any condition, in
any specialty. First is to alleviate symptoms (section 3). The second is
to prevent morbidity and mortality (section 4), even in patients
without symptoms. There are NO OTHER REASONS TO TREAT A
PATIENT. A treatment is recommended to help a patient, either
by reducing the symptoms or by improving the outcome (e.g. longevity
of patient) . If the patient has no symptoms and the condition
is not helped by the treatment, then there is no role for the
With few exceptions, patients come to a physician
because of symptoms. In Cardiac Electrophysiology, the most
common symptom is palpitation, racing heartbeats, or fainting
spells. The primary goal for any treatment, therefore, is the
alleviation of symptoms, taking into consideration the
"risk/benefit" ratio. Take PAC
again for example. This benign condition should be treated if
patients have significant symptoms of palpitation, which may be
extremely disabling and
troublesome for some patients. In these cases, one may accept
a treatment that may have potential side effects as long as the
benefit outweighs the risks. Management of another condition,
which can cause disabling symptoms, is also governed by the same
principle. A patient with this condition who has frequent
attacks and multiple ER visits would best be served with a treatment
like radiofrequency ablation which can eliminate
the source of SVT and cure this condition. Both PACs and SVTs
are considered "benign" conditions, as they usually do not lead to
fatality. Therefore, reason for treating these conditions is
alleviation of symptoms.
4) Preventing Morbidity and Mortality.
second principle of treatment is just as important, if not more
important, than treating symptoms. One of the central
goals in medicine is prevention of premature deaths, an example of
which is high cholesterol treatment. Most patients with high
cholesterol do not have any symptoms specific to the condition of
high cholesterol because there is none. However, high cholesterol
can cause hardening of the arteries and heart attack; most
physicians would consider treatment of high cholesterol mandatory even though these patients have
no symptoms whatsoever. Cancer screening (breast, colon,
prostate, etc) in asymptomatic high risk
patient is another example.
In Cardiac Electrophysiology,
the same principle holds for the management of arrhythmias. Treatment with coumadin for prevention of stroke in
atrial fibrillation is a classic example. Atrial
fibrillation is one of the most common preventable causes of stroke
and the treatment with coumadin, a blood thinner, can prevent
stroke. In this case, Coumadin does
not improve symptoms of patients with atrial fibrillation
whatsoever, but it is one of the most important treatments because it prevents a devastating morbidity
and potential mortality of
Similarly, recommendation for a
prophylactic (preventative) defibrillator
implantation in high risk patients who may have not any symptom is
another important example of this principle of treatment.
Cardiac patients with severe dysfunction of their heart are at high risk for
cardiac death. They can be completely
until they actually suffer an
event, by which time it is too late. Ironically, when patients do suffer sudden death, they
frequently have no symptoms because death is instant. Thus, it
is obvious why one does not wait for symptoms of sudden death to
occur before recommending a defibrillator.
every physician strives to provide the best treatment recommendation
for his or her patients, there are many factors that influences the
physician's opinion, one of which is his or her own anecdotal
experiences. A physician who recently referred a patient for a
surgery and the patient suffered a complication may be "gun-shy" the
next time he or she considers referring a similar patient, even
though it may have been a 1 in a 1000 occurrence of that complication.
On the other hand, a physician who never referred any patients
for certain procedures probably does not have sufficient experience to
make any reasonable recommendation for or against the procedure.
The experience of the physician or surgeon performing a certain
procedure is also critically important. A physician or surgeon who
has performed a large number of certain procedure would be more
comfortable with that procedure, and consequently more inclined to recommend it
than another physician who has little or no experience with it. The
latter physician may recommend an alternative procedure which he or
she is more experienced with but which may or may not be a superior
procedure than the first one. Asking your physician and
surgeon about his
or her clinical experience is a completely legitimate (though
sometimes embarrassing) question to ask at the time of your
Myths in Treating Arrhythmias:
My neighbor had it done. Why Can't I?
Even though all men are created equal (not really), all arrhythmias
are not. Just because your neighbor had a certain procedure
done for his arrhythmia and he is feeling great, it does not mean
that you have the same condition or that you will benefit from the same
procedure. There are many different arrhythmias, and treatment
options vary dramatically from one arrhythmia to another. Your
physicians, not your neighbor, would be a better person to provide
My friend had a friend who died after a
defibrillator. I will never have one myself.
This myth, unfortunately, is another one that
influences patient decision on medical therapy, sometimes more so
than any other factors. Patients sometimes trust the medical
opinion of a friend or a neighbor more than that of their physician.
every medication, and every surgery has its inherent
risks, but the mere presence of risks does not mean that one does
not accept the treatment (see risk/benefit
analysis section). To decline a procedure simply because it
has some risks is like giving up driving a car because there is the
risk of car accident (unless, of course, the risk is so high because
of the driver or the car. Here the problem is the driver or
the car, not "driving" per se).
Furthermore, cardiac patients who undergo procedures
are generally very sick and elderly patients. It is not
unexpected that some patients can still die after a defibrillator is
implanted (This does not mean that the defibrillator caused
the death; risks of death from a defibrillator surgery is in the
order of 1 in 1000 or less). On the other hand, there are
countless number of patients whose lives have been saved by the
defibrillators and these stories do not always make the "headlines."
Like every field in medicine, one must consider both the
benefits and the risks, not just the risks, in deciding on any
I get bruises easily. I can't take
risk/benefit analysis should be
considered in any medical decision, including that for medications
like coumadin. Coumadin in high risk patients can prevent a
devastating stroke. The risk of not taking coumadin (stroke)
is significantly greater than the risk of taking it (bruises).
For most patients, having a stroke is worse than having skin bruises
or other bleeding complications, unless you have a modeling career.
4) I won't take that rat poison!
Coumadin is a blood thinner and it is derived from rat poisoning.
It is currently the standard of care in patients at high risk for
stroke, such as atrial fibrillation or mechanical valve. It's
level must be carefully monitored and dosage adjusted according to
the level (see coumadin
clinic). Although rats do die from rat poisoning, there
are important differences between rat poison and coumadin. Rat
poison are given to rats in toxic and lethal dosages to cause
massive bleeding, whereas coumadin is administered in tightly
titrated dosages. In carefully monitored patients, coumadin is
5) I don't want any machine in me!
Many therapies in Cardiac Electrophysiology consist of implanting
high-tech medical devices, such as pacemaker or
defibrillator. Patients sometimes jokingly
refer to themselves the "bionic man." Having a "machine"
implanted in the body, however, is neither a new concept nor
particularly unusual. Patient with broken bones or severe
arthritis have had metal prosthesis implanted for decades. We
live with and around machines everyday, including watches, cell
phones, computers, automobiles, and hearing aids. Pacemakers
and defibrillators are just sophisticated "machines" that are
implanted inside the body to improve our health, not much different
than those outside the body that improve our lives.
6) It's not "natural."
Many patients who subscribe to the "natural" theory of healing their
medical conditions are strong opponents of many therapies in Cardiac
Electrophysiology. Clearly, all medications are "synthetic" and no
treatment is "natural." The only thing natural is to let the
condition run its natural course (physicians call this "natural history of
disease"). Every human intervention to alter the natural
history of a disease is, by
definition, "unnatural." For argument sake, here are a few
examples of "natural" things in life: bacteria, virus, pneumonia,
and "natural disasters" like earthquake and tsunami.
And here are
some examples of "unnatural" or synthetic things: antibiotics, nurses,
hospitals, cars, phones, computers, and houses. Your reading this
paragraph on an LCD screen over the internet is not "natural."
Hospital Based Procedures for Treating Arrhythmias
The previous paragraphs discussed general
treatment principles in dealing with arrhythmias. The
following section goes into detail about some of the more commonly
performed Electrophysiology procedures. Not every procedure is
meant for every patient with arrhythmias, and not every patient will
need a procedure. This section deals only with procedures
most of which are invasive and hospital-based. For specific treatment
options for each arrhythmia type,
please refer to the section on "Different
Types of Arrhythmias."
Electrophysiology study (EPS).
This invasive study is generally needed for patients whose causes
for fainting or severe palpitation remain unknown despite extensive
noninvasive evaluations. It is also useful to differentiate
the various causes for a documented episode of arrhythmia. It
can be used to risk-stratify certain patients with known or
suspected arrhythmias. Lastly, it is performed in conjunction
radiofrequency ablation, as a mean to confirm the mechanism of the arrhythmia
before performing curative ablation.
The procedure is performed in a hospital setting
in the cardiac catheterization laboratory, the same facility where
coronary angiogram and angioplasty are performed.
Under sedation, lidocaine (or equivalent local anesthetics) is
injected into the skin. Several catheters are then inserted
into veins in the groins and into the heart
(see picture), after which electrical stimulation of the heart is
performed through these catheters by the Electrophysiologist.
These electrical stimulation can reveal an underlying electrical conduction
problem such as slow heartbeat or
heart block, as well as reproducing and confirming the cause of
a rapid heartbeat.
For patients with rapid heartbeat problem, they do not necessarily have to be in their
arrhythmia at the time of the procedure since this test can
"provoke" the dormant arrhythmia.
If a slow heartbeat is documented, one can prescribe the
appropriate treatment, usually a
If a fast heartbeat is confirmed, there are several treatment options, depending on the type of rapid heartbeat discovered.
For some rapid heartbeat that are potentially life-threatening, such
ventricular tachycardia, an
defibrillator is required. On the other hand, for many
other forms of rapid heartbeats, such as
the arrhythmias can be
"mapped" to determine the exact source of the problem,
which is usually an "extra nerve" in the heart.
In the majority of these cases, ablation can successfully eliminate the
culprit of the arrhythmias, resulting in a long-term permanent cure
for the patient.
Thus, an Electrophysiology study is a diagnostic
study that helps the Electrophysiologists confirm the root of the
suspected electrical problem of the heart. It serves as a gateway to
other therapeutic modalities available to treat the arrhythmias.
Many patients who have serious symptoms from
their rapid heartbeat, such as fainting or near-fainting, may be
very reluctant to have a test which can provoke their arrhythmias,
for fear of reproducing the frightening sensation.
Reproducing the arrhythmia, however, may be the only way to confirm
the causes of their conditions in most patients. Furthermore,
there is no safer place to have an arrhythmia than in the cardiac
catheterization laboratory, under the direct care of a Cardiac
Electrophysiologist, and in the presence of an entire team of
personnel specializing in the chronic as well as emergency
treatment of arrhythmias. It is better to find it here than to
have it occur "naturally" at home or while driving on the road.
In contrast to an coronary angiogram, which is a procedure designed to look
for clotted arteries of the heart (coronary arteries), an
is not meant to
evaluate the patency of patient's arteries. But rather, it
focuses on the evaluation of the electrical health of the heart.
One, therefore, can not tell "if the arteries are blocked" by this
test. This is the job for your general or interventional
Radiofrequency ablation (RFA). This is
a cardiac procedure specifically designed to treat and cure certain types
of arrhythmias (see sections on
Wolff-Parkinson-White Syndrome, and
Ablation is a procedure of selectively destroying certain tissues
of the body to cure or control a disease process. An ablation
can be performed for seizure focus in the brain or for certain
masses in the liver, or for abnormal electrical activities in the
heart. Cardiac ablation refers to ablation specific to the
heart rhythm problem. The most common source of energy for
cardiac ablation is radiofrequency and thus the most common term for
this procedure is "radiofrequency ablation," although other sources
of energy have been used.
For cardiac ablation, very thin catheters are
placed into the heart via large veins in the groin and sometimes
in the neck (see picture above). This is why the procedure
is also called "trans-catheter ablation," to distinguish it from
open-heart surgical ablation. The procedure is done much like
that of an Electrophysiology study, which
is first performed to identify the source of the arrhythmia.
"Mapping" is done to localize the source of the problem, after
which ablation is performed targeting and selectively destroying the
areas that are responsible for the arrhythmias.
For the purpose of discussion on this website, the term
"radiofrequency ablation" means cardiac ablation procedures
performed "percutaneously," or "endocardially" through a catheter
In other words, they are performed by a minimally invasive technique
via a vein or artery through the skin (percutaneous), not by an
open-chest or open-heart surgery. The approach is from
inside the heart (endocardial), because the catheters enter the
heart on the inside, as opposed to outside the heart (epicardial)
as in open-heart surgery. In the latter case, the approach is through a
surgical opening in the chest and these epicardial ablation
procedures are done by cardiothoracic surgeons, not by Cardiac
Cure rates for most forms of arrhythmias by radiofrequency
ablation range form 80% to 98% (please see
on specific arrhythmias for individual discussion).
Complications rates are low, with mortality less than 1 in several
thousand and very small risks of bleeding and perforation.
For many types of arrhythmias, radiofrequency ablation is increasingly accepted as an
preferred therapeutic alternative to chronic therapy with medications. It is considered first-line
therapy for most curable arrhythmias such as
Wolff-Parkinson-White Syndrome, and
This is a specialized mapping
technique which utilizes a computer to delineate the source of
complex arrhythmias. It works by projecting a virtual
3-demensional image of the heart in the computer to help the Cardiac
Electrophysiologist navigate his catheters, in ways very similar to what GPS does
for driving a car or flying an airplane.
For many types of ablation, such as those for atrial
fibrillation, 3-D mapping is essential to ensure optimal success
rates and safety for the patients. For further discussion on
this technology, please click this
link to St. Jude Medical.
This is a procedure used to electrically convert a sustained
abnormal heart rhythm back to the regular normal rhythm (normal
sinus rhythm). The most common arrhythmias that require
ventricular tachycardia may need to be treated with
cardioversion on an emergency basis..
Under anesthesia, an external electrical shock is applied to the
heart through the chest. An external defibrillator is used to
deliver the shock through its "paddles." The electricity that
is transmitted through the chest into the heart will instantly stop an arrhythmia and restore
normal regular rhythm. The risk of the procedure is fairly low.
Other than the risk of minor skin burn and some risks associated
with light anesthesia, the procedure is very safe, effective, and
easy to perform. One risk that deserves mention
is that of blood clot and stroke in patients with atrial
fibrillation or flutter who undergo cardioversion. The risk is
negligible if patients with these conditions have previously been
treated with a blood thinner, or coumadin. One should not
proceed with cardioversion if one has not been therapeutically
treated with coumadin for at least 3 weeks, unless an ultrasound of
the heart done through the esophagus is first performed
(trans-esophageal echocardiogram) to rule out the presence of a clot
in the left atrium.
Pacemaker (PM). A pacemaker's is a medical
device used to regulate the heart rate and to keep it from beating
too slowly. Therefore, the most common indication for a pacemaker
in a patient is slow heartbeat or
heart block. Patients with
fainting spells due to slow heart rate are also candidates for
pacemaker implantation. The latest indication for pacemaker is
cardiac resynchronization therapy for pacing with
congestive heart failure.
system consists of the "pulse generator" and the "lead." The
pulse generator is where the battery and the electronics reside.
It is the "brain" of the pacemaker. It is connected to a
"lead," or a wire, through which the "brain" of the pacemaker
communicates with the heart. The connection
between the lead and the pulse generator is called the "header."
Most pacemakers in use today are "dual
chamber" pacemaker because they utilize two electrodes, which are
placed respectively in the atrial and ventricular chamber, thus
"dual chamber." (See
anatomy and physiology section). The advantage of such a system is that is
preserves the normal physiology of the heart, i.e., normal
relationship between the upper chamber and lower chamber. A "single chamber" pacemaker uses
only one electrode, which can be placed in either the atrium or the
ventricle. A single chamber pacemaker is less frequently used
in the U.S. because it does not preserve the normal relationship
between the upper and lower chambers of the heart. A single chamber pacemaker is most commonly
used when when such a normal relationship is no longer present in
patients with chronic atrial fibrillation.
surgical implantation of the pacemaker system, the leads are
inserted through the vein on the chest. They are subsequently
placed permanently inside the chambers of the heart whereas the
"pulse generator" itself is implanted on the chest just under the skin
the procedure is done transvenously (through the vein), it does
not require an open heart surgery. This surgery can be completed in
as short as 20 minutes and is associated with reasonably low risks
and rapid recovery (see also
asked questions section).
Major complications are rare but may include cardiac perforation,
pneumothorax (air leak in the lung), vascular injury, and hematoma
(blood clot). Infection of the pacemaker may occur in 1
percent of the time which will require explantation of the entire
While older generations of pacemaker has only one function and
that is pacing the heart, newer generations of pacemakers have the
capability of cardiac resynchronization therapy (CRT).
They can be used in patients without slow heartbeat but who suffer
from heart failure
refractory to standard medical therapy.
Implantable Cardioverter Defibrillator (AICD or ICD).
A defibrillator is a medical device whose primary function is to shock the heart when
the heart has gone into a very rapid and life-threatening arrhythmia
ventricular tachycardia. Its secondary
function is to pace the heart when the heart rate is too slow.
A frequent question that comes up is whether a particular device
is a "defibrillator" or a "pacemaker" or a "combination." A
pacemaker simply paces the heart when it is too slow. It has
no defibrillator function, i.e., it can not "shock" the heart in the
case of an emergency. A defibrillator, on the other hand, can
pace the heart when it is too slow, and shock the heart when it is
too fast. All defibrillators today can also work as pacemakers, and
therefore the concept of a "combination" pacemaker-defibrillator is
no longer relevant. There are no defibrillators today that
work only as a "shock box" without full pacemaker capability.
The converse, however, is not true.
A defibrillator is used to treat patients with life-threatening
arrhythmias. When first invented in the 1980s, defibrillators
were reserved for patients who have already suffered a
cardiac arrest or have documented
arrhythmias. However, most defibrillators today are
implanted on a
basis, i.e., preventatively. In other words, they are
implanted in patients at high risk for a serious arrhythmia and
cardiac arrest but who have not yet suffered such an event.
While this idea may be difficult for some patients and even some
physicians to accept, prophylactic defibrillator implantation is no
different, conceptually, than treating hypertension or
hypercholesterolemia for prevention of heart attack. One does
not wait for cardiac arrest to occur before implanting a
defibrillator, just as one does not wait until a full blown heart
attack to take place before treating patient's elevated blood
pressure and cholesterol. Current recommendation is for
defibrillator implantation in patients with an
less than 35%.
The anatomy of a defibrillator is very similar to
that of a pacemaker, except that the size of the pulse generator and
the electrodes are significantly bigger and the structures more
complicated. This is because the defibrillator needs to
deliver higher energy to shock the heart than what is required to
pace the heart. The placement of the electrodes inside the
heart is also more critical that that for the pacemaker because the
effectiveness of the "shock" function depends greatly on the
location of the electrodes.
Similar to pacemakers, defibrillators are inserted transvenously
(through the vein) and therefore do not require an open heart
surgery. Surgical risks are similar to those with pacemaker (see
asked questions section).
Once implanted, a defibrillator monitors every single one the
patient's heartbeat, day in and day out, 24/7, for any serious
arrhythmia. The very second the heart slips into a dangerous
rhythm like ventricular fibrillation (left side of the above
diagram), the defibrillator instantly recognizes the problem,
charges up its capacitors, and delivers a high voltage shock to the
heart to restores regular rhythm (right side of the diagram).
Cardiac Resynchronization Therapy (CRT).
This is a percutaneous (through the skin) surgical procedure specifically for the treatment of patients with severe
congestive heart failure.
In patients with heart failure, the left
ventricle is enlarged and
the time it takes to activate the entire heart may be significantly
leading to "dyssynchrony," or lack of synchronized or coordinated
contraction of the heart. This usually manifests itself as
abnormal EKG with either
right bundle branch block or
left bundle branch block. The larger the heart and the greater
the degree of dyssynchrony (as assess by
EKG), the more one would benefit from CRT.
CRT works by pacing both the right and left side of the heart
simultaneously, shortening the time to activate the heart and
restoring "synchrony" to the heart, thus the term "Cardiac
Resynchronization Therapy (CRT)."
A CRT device can be a CRT pacemaker or a CRT defibrillator.
Most CRT devices implanted in the U.S. are the defibrillator type
because most patients with heart failure who need CRT will also
need a defibrillator.
A CRT device works by having a "third wire" capability to pace the
left side of the heart.
Ordinary pacemakers and defibrillators come with two wires, one in
the right atrium and one in the right ventricle (RV). CRT pacemakers and
defibrillators have an extra wire which goes into the left ventricle
(LV), via a
vein in the back of the heart called "coronary sinus."
The branches of the coronary sinus are called "coronary veins,"
through which the "third-wire" is placed in order to pace the left
side of the heart (see diagram below). Simultaneous pacing of both right and left ventricle can be
performed through these wires in order to "resynchronize"
the heart. This can result in dramatic improve symptoms
of heart failure for those patients with heart failure and dyssynchrony. Most patients
with CRT implantation will
experience improvement in their breathing, stamina, and exercise
ejection fraction and other important parameters of the heart
may also improve.
For a CRT defibrillator, the CRT portion of the device is an
added feature of the unit. In other words, the device can
provide CRT while still functioning as a defibrillator. A
standard two-wire defibrillator works as a defibrillator without CRT
Although CRT has been available since the late
1990s, it has only recently gained wide-spread acceptance and popularity
following the publication of several large landmark
clinical trials which
demonstrated significant improvement in heart failure patients who
have received CRT. Today, CRT is considered a standard of
care for patients with heart failure and evidence of
dyssynchrony, who continue to have refractory
symptoms of heart failure despite optimal medical treatment.
Risks of the surgery is similar to those of the pacemakers and standard
defibrillators. The additional "third wire" placed in the left side of
the heart used to be a critical step that was difficult to achieve
and took many hours. Today, with improved technique and
equipment, the deployment of the "third wire" for CRT may take as few
as an extra 10 minutes compared to the standard pacemaker or