Methods doctors use to diagnose arrhythmias include:
Electrocardiogram (ECG or EKG)
This is a simple test in which patches with wires (electrodes)
are attached to your skin to measure the electrical impulses given off by your
heart. Impulses are recorded as waves displayed on a monitor or printed on paper.
This is a portable version of an ECG. It's especially useful
in diagnosing heart rhythm disturbances that occur at unpredictable times. The
monitor is worn under your clothing. It records important information about
the electrical activity of your heart as you go about your normal activities
for a day or two.
For arrhythmias that occur sporadically, your doctor may ask
you to wear another portable device called an event monitor. Two types exist.
One type, called a loop recorder, is like a Holter monitor but is worn for a
longer period of time. When you experience symptoms of an arrhythmia, you push
a button on the device to record your heart's rhythm. The other type of event
monitor is a credit card-shaped device that you place on the skin over your
heart whenever you experience symptoms. The card records your heart rhythm.
Both devices help your doctor determine whether abnormal heart rhythms are present
at the time of your symptoms.
Your heart naturally speeds up during exercise or excitement,
which can trigger an arrhythmia. Stress tests, which come in many variations,
are used to help identify arrhythmias triggered by exertion. In one type of
stress test, you may be asked to walk on a treadmill while hooked up to an ECG.
In another you may be hooked up to an ECG and then given a drug that stimulates
your heart in a way that's similar to exercise.
In Electrophysiologic testing, electrodes attached to a long,
thin tube (catheter) are threaded through a vein in your arm or leg to your
heart. Once in place these electrodes can map the spread of electrical impulses
through your heart. These electrodes can also give off electrical impulses of
their own to pace your heart and see how it reacts. This type of testing is
useful in determining what type of arrhythmia you may have and where the problem
occurs in the heart. During the procedure, many arrhythmias also can be treated
by means of catheter ablation — a procedure used to destroy heart muscle
cells responsible for an arrhythmia.
A tilt-table exam is a way to test for causes of fainting,
which could be a symptom of an arrhythmia. Your heart rate and blood pressure
are monitored as you lie flat on a table. The table is then tilted. The changing
angle puts stress on the part of your nervous system that maintains your heart
rate and blood pressure. Doctors can see how your heart responds to the change
in angle — similar to the change in angle when you go from lying down
to standing up.