How Are Diagnoses Made for
"Arrhythmia" means "irregular heartbeat" in
English. The term "arrhythmia," therefore, is not a diagnosis,
but a general term describing many different conditions that share
the commonality of irregular heartbeat. Some patients,
unfortunately, even after extensive diagnostic evaluation, are said
to have suffered from an "arrhythmia." Diagnosing someone as
having an "arrhythmia"
is like saying
that the patient has a "heart condition." It is vague and
provides little or no useful information for the patient or for the
next physician taking care of the patient. For, there are many
different types of arrhythmias with widely varying
severity of symptoms, and, more importantly, markedly different
There are literally dozens of different types of
arrhythmias. Some arrhythmias can kill a patient instantly
while others are completely benign. Some can cause severe
symptoms like racing heartbeat and
fainting spells while others may produce absolutely no symptoms
whatsoever. Making a specific diagnosis of the type of
arrhythmia the patient has, therefore, is of paramount importance.
As a general rule, in order to make a diagnosis of
an arrhythmia, some forms of electrocardiographic recording (i.e.,
EKG, Holter monitor, or
event monitor) must be made at the time the
arrhythmia is occurring. Evaluation by symptoms alone is
inadequate. This is because symptoms from different
arrhythmias may feel exactly the same to a patient, and the same
arrhythmia may feel differently for different patients. For
example, the sensation of palpitation can occur in patients with
ventricular tachycardia or with
two conditions with vastly different prognoses. The physician,
therefore, usually can not diagnose one arrhythmia from another
based on symptoms alone.
In addition, in between episodes of arrhythmias,
the EKG can be completely normal, making the diagnosis quite
challenging. A very common scenario is a patient with an
(a very rapid arrhythmia) who has an episode of attack once a month,
lasting 10 minutes each. Every time this patient runs to the
emergency room, the SVT has already stopped and the EKG in the ER is
completely normal. Many such patients have been misdiagnosed
as "panic attack" or "anxiety" because of the lack of physical
evidence (other than patient's subjective report of symptoms) of an
arrhythmia. Some patients even leave the ER with a diagnosis
of "palpitation," which is a symptom, not a diagnosis. The
true diagnosis can be quite elusive until one day when an EKG is
finally done at the time an episode is still ongoing.
If an arrhythmia becomes persistent and is present
day-in and day-out, as often is the case for
atrial flutter, the diagnosis is quite easy with a routine EKG
done in the physician's office. The challenge is when an
arrhythmia occurs intermittently (on and off) or is self-limiting,
whereby a EKG performed in between attacks can be completely normal.
To circumvent this problem, one would go to the next level of
evaluation with a long-term monitor.
Long-term monitors basically are EKG recorders
that patients can take with them. They fall into two major
categories. A "Holter monitor" records
continuously the EKG of a patient, usually for 24 hours.
The advantage of a Holter is that every single heartbeat during that
day is recorded and can be analyzed. The disadvantage is that
if an arrhythmia did not happen on that particular day, the
Holter would not be useful. An "event monitor,"
on the other hand, is a long-term monitor that can be used for up to
30 days at a time. The advantage is that the longer the
recording period, the better chance of "catching" an intermittent
arrhythmia. The disadvantage is that an event monitor must be
activated by the patient and downloaded through a telephone line, a
task that requires certain amount of manual dexterity and may be
difficult for some patients.
For certain arrhythmias which are so rare that
they occur once or twice a year, the diagnosis can be nearly
impossible to make with any of these monitors. In these cases,
or in patients who are not capable of handling an event monitor, an
implantable monitor is available that can
monitor patients' rhythms for up to 2 years, continuously, 24/7.
The major advantage of this monitor is the length of time of
monitoring compared to other monitors. The disadvantage is
that it requires a surgery, though a very minor one that takes about
5 minutes to complete.
For many patients, both Holter monitor or event
monitors, or even implantable monitors may be necessary because
these different monitors have different capabilities and complement
each other. However, if the diagnosis remains elusive after
extensive evaluations with these "passive" tests, a "proactive" test
may be necessary.
A "passive" test waits for an arrhythmia to occur
spontaneously before making a recording. This can be time
consuming and sometimes a diagnosis simply can not be made despite
extensive evaluation. In those cases, a "proactive" approach
may be necessary whereby the physician actively "provokes" an
arrhythmia in order to make a recording of it for a diagnosis.
This "proactive" approach may involve simply
having patient engage in activities which historically have provoked
patient's symptoms, while the patient is wearing a monitor.
For example, certain arrhythmias that occur consistently during
physical activities or after ingestion of alcohol may be reproduced
with these activities during a monitoring period.
For conditions that occur with exercise, a
treadmill stress test supervised by your
physician sometimes can reproduce an arrhythmia, helping to clench
the diagnosis. A similar test monitoring the "T
waves" of the EKG can help reveal underlying conditions that can
cause serious arrhythmias. For certain conditions that cause
fainting spells, a tilt table study can
recreate an episode and help reveal a cause.
Lastly, when all else fails and the diagnosis
remains uncertain, an electrophysiology study can
be done to confirm or exclude certain arrhythmia diagnoses.
This invasive test is also done in conjunction with
In summary, there is an extensive battery of
diagnostic tests for patients with symptoms suspicious for
arrhythmias. These tests range from simple and routine to
complex and invasive. Different tests have different yields
for diagnosing an arrhythmia and not all tests are appropriate for
every patient. Your physician can made the decision on which
tests are appropriate for your particular condition.
physician may evaluate patients with suspected arrhythmias
a general rule is usually
followed. Most physicians would recommend starting with the
least invasive (which, incidentally, may have the lowest yield) and
progress to the most invasive tests if the diagnosis still remains
unclear. On the other hand, for certain patients with serious
presentations (e.g., a fainting spell that resulted in a major car
accident) or patients whose line of work involves the safety of
others (e.g., a commercial airline pilot who suffers from loss of
consciousness), the physician may elect to bypass the low-yield,
non-invasive tests and go directly to the more invasive evaluations.
The following paragraphs describe in detail some
of the most common diagnostic procedures a physician uses in the
evaluation of patients with suspected arrhythmias.
Office and Hospital Based
Diagnostic Procedures for Arrhythmias
(EKG). This is the most basic and standard
initial evaluation for patients with a suspected arrhythmia. An
EKG is a window into the electrical activities of the heart.
Multiple electrodes (stick patches) are placed
on the arms, legs, and over the chest area in order to record
electrical activities of the heart from different angles of view.
The heart generates electrical activities with each heartbeat, which
can be detected by the voltage difference between pairs of
electrodes and translated into graphical display on paper.
Today's standard EKG utilizes 12 electrodes, thus the name "12-Lead
EKG." An EKG is most
useful in diagnosing an ongoing arrhythmia at the time the EKG is
being performed, but it is not useful if the arrhythmia, or the
symptoms suspected to be due to arrhythmia, is no longer present at
the time of the evaluation. Keep in mind that an EKG is a
static picture, or a "snap shot," of what is happening in the heart
at the time the recording is made.
Holter monitor. This is an EKG
recorder that continuously
records every heartbeat of a patient for a period of usually 24 hours.
Rather than having 12 leads, most Holter monitors utilizes 3 leads.
Patients are usually "hooked up" with a Holter while in the
physician's office, wearing it for 24 hours, then returns the next
day to have it removed in the office. Patient may not shower
and should avoid strenuous activities (unless specifically
instructed by the physician) during the recording period. At
the end of the 24 hour period, patient may remove the unit on his or
her own and bring the unit back to the office for analysis.
The recording of the heart rhythm on a Holter is made in a
continuous fashion onto an electronic media, which is then
downloaded into a computer and analyzed beat-by-beat. This test is most
useful if an arrhythmia is there all the time, or occurs frequently
enough to be "caught on tape" during that 24-hour period
of recording. It is therefore very important for the patient to write down in the
any symptoms that occurred during the recording period, so the physician
can correlate the symptoms to actual arrhythmias found on the
One important limitation of a Holter monitor is that it records
only during that 24 hours of time and may miss an infrequent
arrhythmia. In other words, an arrhythmia that occurs only a
few times a year is unlikely to be "caught" by chance during any
single 24-hour period of recording. In those cases, a long-term
event monitor may be the preferred choice of test.
Event monitor. An event monitor is a
long-term (usually 30 days) monitoring device that records "patient
triggered" events. Similar to an EKG or a Holter
monitor, it records the electrical activities of the heart via
electrodes placed on the patient's chest. The electrodes and
wires are attached at all time to patient's chest and can be taken
off and replaced as needed for shower and other activities where
patients may not wish to have the hardware attached.
a Holter monitor, which records continuously, the event
monitor records only when activated by patients. In other
words, while the monitor continuously keeps a "loop" memory, the
actual recording of the heartbeat and writing of the data onto the
electronic media occurs only when patient triggers the
recording by pressing a button on the unit. This is so that
the physician can correlate patient's symptoms to what is recorded,
thus confirming or refuting the cause of patient's symptoms being of
arrhythmic origin. A major advantage of a loop-recorder is
that it always keeps the preceding 40-60 seconds of data in the loop
memory, such that if a patient was not able to trigger the recording
immediately at the time of the symptoms, but does so a short time
later, the data may still be useful.
Some newer types of event monitor have automatic recording
capability. Rather than waiting for patients to make a
recording during symptoms, these devices can detect asymptomatic
episodes of arrhythmias. This is most useful in patients with
atrial fibrillation. However, in contrast to the
traditional patient-triggered event-recording, the automatic
recording is NOT used to help explain patient's symptoms (as it is
not patient-triggered), but to detect sub-clinical, or "silent"
Another type of event monitor is so-called
"non-loop" event monitor. They usually come in the shape of a
credit card. Unlike the loop-recorders, this unit does not
have to be attached through electrodes to the patient at all time.
One simply can keep such a card in his or her pocket or purse, and
can apply it to the chest whenever an episode of arrhythmia occurs.
Although most patients may prefer this type of event monitor because
of comfort and convenience, it does not have "loop" memory since it
is not attached to the patient all the time. The recording
will start only after it is placed on the chest and
activated. For some arrhythmias that are very short in
durations, i.e., seconds, by the time the unit is applied
appropriately on the chest and recording started, the arrhythmia may
have been missed. Furthermore, this type of monitor is not
useful for diagnosing
syncope, or fainting spells. For, without a loop memory,
by the time a recording is made, the event that initially caused
fainting may already have passed.
For any type of event monitors, once a recording is made
successfully with patient activation, the data can then be
downloaded through the telephone to a centralized station, which in
turn faxes the EKG tracings to the physician on record. The
physician can then correlate findings on the recording with
patient's symptoms. After 30 days of monitoring, patients
would usually make an appointment with the physician to review the
There are two major advantage of the event monitor over the Holter
monitor. One is that a patient can keep the event monitor for
an extended period of time (usually 30 days and renewable),
maximizing the chance of recording an infrequent or intermittent
arrhythmia. The yield for a diagnosis is directly proportional to
the length of the recording, based on probability and statistics.
The other is that because the recording occurs only when triggered
by the patient (for the traditional event recorders), the physician
can determine whether patient's symptoms are actually caused by an
arrhythmia. In other words, if a patient feels severe
palpitation while concurrent monitor recording showed only normal
regular heartbeats, one can safely conclude that the symptoms are
not due to arrhythmias.
One disadvantage of an event monitor compared to a Holter is that,
too frequently, patient may "forget" to have the monitor close by
during an episode, or that a patient may be in a social situation in
which making such a recording (the unit may make loud beeping
sounds) may be socially unacceptable. Yet for other patients,
making a recording and downloading the information over the phone
may be more than the manual dexterities of the patients can handle.
This is when an implantable loop recording can be helpful.
Implantable Loop Recorder. When
testing fail to identify an arrhythmia and yet arrhythmia is still
suspected as the cause of patient's symptoms, the physician may
recommend proceeding to insert an Implantable Loop Recorder.
The idea of an implantable loop recorder is identical to that of a
traditional event recorder. It records specific patient
triggered event to help the physician explain patient's symptoms.
However, the main difference is that this unit is implanted
surgically on the chest so that it is there all the time.
Patient simply can not "forget" to bring the unit with him or her,
nor would feel uncomfortable "making a scene" in public since the
unit can record automatically. The unit is there 24/7 for 2
years and faithfully records the information continuously in a loop
memory, and writes onto the hard memory when triggered by patient or
when an automatic detection algorithm is met. The automatic
algorithm usually triggers a recording when the heartbeat is either
too fast or too slow, conditions that can cause symptoms of
palpitation, lightheadedness, or fainting spells.
This very small (about 1x3 inches) device is implanted just under
the skin on the chest, a surgery that usually takes about 5 minutes
to complete and is done on an outpatient basis. The recorder
uses its built-in electrodes on the unit to make recording of the
heart rhythm. The internal battery can last 18 to 24 months.
The major advantages of this type of recorder are two folds. One
is that a patient will never "forget" to bring the recorder with him
since it is already implanted under the skin. Secondly, among all
monitors, the implantable loop recorder has the best chance of
recording an arrhythmia that occurs very infrequently (i.e., once a
T-Wave Alternans. This is a treadmill
stress test that specifically evaluates patients for risk of serious
sudden cardiac death. It records microscopic changes
in the T-Wave (a part of your EKG) not visible to the naked eyes.
It has been shown to be very effective in differentiating patients
who are at low risk versus those who are at high risk for sudden
Tilt table study. This simple and noninvasive
test evaluates patients with dizziness and fainting spells (syncope).
Specific diagnoses such as vasovagal syncope, neurocardiogenic
syncope, postural orthostatic tachycardia syndrome, and carotid
hypersensitivity syndrome can be made this study.
The test is usually done on an outpatient setting
after an overnight fast. The patient, strapped to a tilt table
to prevent accidentally falling off the table, is tilted to about 75
degree angle and monitored with EKG and blood pressure recording
continuously for 20 to 45 minutes. For patients with recurring
fainting spells, the underlying cause of fainting can be revealed in
about 50-75% of the cases.
In order for the diagnosis to be made, however, the fainting or
near-fainting episodes must be reproduced during the test.
While this may sound disconcerting, this is the only way to confirm
a diagnosis. Furthermore, there is no better place to have a
fainting spell than when under the direct care of a Cardiac
Electrophysiology study (EPS). This invasive study is generally
needed for patients whose
cause for fainting or severe palpitation remains 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
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.
Several catheters are inserted through the veins in the groins into the heart
(see picture), after which electrical stimulation of the heart is
performed through these catheters by the Electrophysiologist.
This provocative test 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 arrhythmia which the patient chronically suffers from.
Therefore, patients do not necessarily have to be in their
arrhythmia at the time of the procedure.
If a slow heartbeat is documented, one can prescribe the
appropriate treatment, usually a
If a fast heartbeat is confirmed, one of several treatment options
exist, depending on the type of rapid heartbeat discovered.
For some rapid heartbeat that are potentially life-threatening, such
ventricular tachycardia, an
defibrillator is indicated. On the other hand, for the
more benign forms of rapid heartbeats, such as
the arrhythmias can be
"mapped" to determine the their causes and the suitability for ablation.
In the majority of 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. As the initial
invasive Electrophysiology procedure, 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, are often
very reluctant to have a test which can provoke their arrhythmias.
Reproducing the arrhythmia, however, may be the only way to confirm
the causes of their arrhythmias 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
management of arrhythmias.
In contrast to an coronary angiogram, 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.
Exercise Treadmill Test. This is a
diagnostic test used to evaluate patients for the health of their
coronary arteries. Its most common function is to rule out the
presence of hardening of the arteries in the heart in patients with
chest pain. However, for the Electrophysiologist, a treadmill
can serve additional purposes of evaluating causes for fainting,
certain types of rapid heartbeat (e.g. exercise induced
VT), slow heartbeat (2:1
heart block), and can help guide appropriate programming of a
involves placing a patient on an exercise treadmill with
progressively increasing speed and grade, while
monitoring the patient with EKG. An underlying heart
condition can frequently be revealed during the test. This test
is often combined with other imaging modalities, such as
to improve the accuracy of of the test.
Echocardiogram. A noninvasive test, echocardiogram
images the heart in the same way that an obstetrician images
an unborn baby in the womb. An ultrasound probe is placed on
the chest and a real-time beating-heart picture can be seen
immediately on the TV screen. This test is excellent
for detecting enlarged heart and abnormal heart valves such as
aortic stenosis and mitral valve prolapse. It can also detect
abnormalities in the lining of the heart, as well as some areas
outside of the heart. Completely noninvasive, the test uses no dye, no radiation,
and posts virtually no risk to any patient.
For an Electrophysiologist, an echocardiogram can help evaluate
the health of the heart muscle to determine the "ejection
fraction" and the suitability of a
defibrillator. It can reveal certain conditions associated
with arrhythmias, such as Epstein anomaly,
hypertrophic cardiomyopathy, and
arrhythmogenic RV dysplasia.
Tissue Doppler. This specialized test
gives information on how the main pumping chamber of the heart (left
ventricle) works (or doesn't work) in patients with
heart failure. It is an adjunctive
test to a standard echocardiogram. It helps identify patients with
severe heart failure who are
cardiac resynchronization therapy (CRT). CRT is a
specialized pacemaker or defibrillator capable of "resynchronizing"
a failing heart to improve patient's symptoms and heart function.
Stress Echocardiogram. This test combines
an exercise treadmill test with an imaging modality, the echocardiogram.
This improves the ability to diagnose coronary artery disease (clogged
artery of the heart) above and beyond the standard stress EKG test. This test can also be used to evaluate patients
with known or suspected arrhythmias.