Who Needs an Implantable Cardioverter
Defibrillator?
You may need an implantable cardioverter
defibrillator (ICD) if you're at risk for certain life-threatening ventricular
arrhythmias,
such as ventricles that beat too fast or that quiver. For example, you may be
considered at high risk for a ventricular arrhythmia if you:
- Have had a ventricular arrhythmia before
- Have had a
heart
attack that has damaged the electrical system in your ventricles
An ICD is often recommended for people who have
survived
sudden
cardiac arrest.
Your doctor may recommend an ICD if he or she sees
signs of a ventricular arrhythmia (or heart damage that would make one likely)
on the following tests.
Electrocardiogram
This simple and painless test detects and records
the electrical activity of the heart. An
EKG
(electrocardiogram) shows how fast the heart is beating and the heart's rhythm
(steady or irregular). It also records the strength and timing of electrical
signals as they pass through each part of the heart.
Holter Monitor
A
Holter monitor, also called an ambulatory EKG, records the
electrical signals of your heart for a full 24- or 48-hour period. You wear
small patches called electrodes on your chest that are connected by wires to a
small, portable recorder. The recorder can be clipped to a belt, kept in a
pocket, or hung around your neck.
During the 24 or 48 hours, you do your usual daily
activities and keep a notebook, writing down any symptoms you have and the time
they occur. You then return both the recorder and the notebook to your doctor
to read the results. Your doctor can see how your heart was beating at the time
you had symptoms.
The purpose of a Holter monitor is to record heart
signals during typical daily activities and while sleeping, and to find heart
problems that may occur for only a few minutes out of the day. Also, the Holter
monitor can pick up irregular heartbeats that don't cause symptoms, but are
important to treat.
Echocardiogram
This test uses sound waves to create a moving
picture of your heart. An
echocardiogram
provides information about the size and shape of your heart and how well your
heart chambers and valves are working. The test also can identify areas of poor
blood flow to the heart, areas of heart muscle that aren't contracting
normally, and injury to the heart muscle caused by poor blood flow.
Electrophysiology Study
For an
electrophysiology study, your doctor threads a catheter (a
small, flexible tube) from a blood vessel in your arm or leg up to your heart.
Through the catheter, your doctor gives you certain medicines and electrically
stimulates your heart to see how your heart's electrical system responds. The
electrical stimulation helps to find where the heart 's electrical system is
damaged.
Stress Test
Some heart problems are easier to diagnose when
your heart is working harder and beating faster than when it's at rest. During
stress
testing, you exercise (or are given medicine if you are unable to exercise)
to make your heart work harder and beat faster while heart tests, such as an
EKG or echocardiogram, are performed. |