Because many bradyarrhythmias (arrhythmias) occur only
intermittently, devices that record the EKG for longer periods (24 to 48 hours)
are more effective in finding an arrhythmia than a single 10-second EKG done in
a doctor's office. Ambulatory EKG monitors (Holter monitors) will continuously
record your heart rhythm and can be worn while you do your usual activities. A
technologist or doctor can then review the recording to determine whether you
had a bradyarrhythmia during the monitoring period.
Keeping track of symptoms
Your doctor will likely tell you to keep a journal of your
activities and symptoms while you are wearing the Holter monitor so that any
arrhythmia noted can be matched to your symptoms. If you have symptoms that
suggest an arrhythmia, but you have a normal heart rhythm during the symptoms,
in most cases that would mean that an arrhythmia is not the cause of the
symptoms.
What are the limitations of a Holter monitor?
Portable EKG monitors are useful if you have frequent symptoms
that your doctor thinks are cause by an arrhythmia. Obviously, if no symptoms
or arrhythmia occurs while the monitor is being worn, the test is not as
helpful. If your symptoms occur only rarely, even a 48-hour period of
monitoring is not likely to be useful. Prolonged EKG monitoring may also be
useful for monitoring the effectiveness of treatment for the arrhythmia and for
evaluating the function of a pacemaker.
What is an event monitor?
Event monitors are similar to ambulatory EKG monitors (Holter
monitors) except that they are worn for weeks at a time. This type of device
continuously monitors your heart rhythm but stores only several minutes of the
recording in its memory. If you have a symptom that suggests a bradyarrhythmia
(a slow arrhythmia), you can activate the device, which then permanently stores
a recording of your heart rhythm for several minutes before and after the
event.
The stored information can then be sent over the telephone to a
lab that will analyze the recording and discuss the results with your doctor.
This type of monitor can be very useful if your symptoms do not occur often.
Like the Holter monitors, event monitors can be helpful in documenting that you
have an arrhythmia, diagnosing the particular type of arrhythmia, and
determining the relationship (if any) of the arrhythmia to your
symptoms.