Patient education: Ambulatory heart monitoring (The Basics)

What is ambulatory heart monitoring? — This is a way to measure the electrical activity in the heart. "Ambulatory" means that the monitoring happens while you go about your daily life.

Everyone has a built-in electrical system in their heart (figure 1). This is what controls the heartbeat. Sometimes, the electrical signals that control the heartbeat can become abnormal. Abnormal heart rhythms are also called "arrhythmias." Some people have an arrythmia only during certain activities or times of the day.

One way of measuring electrical activity in your heart is a test called an "electrocardiogram" ("ECG"). ECGs are done in the hospital or doctor's office. But with an ECG, the doctor can only measure and record the electrical activity for a few seconds. This can make it hard to diagnose arrhythmias that do not happen all of the time.

Ambulatory heart monitoring uses a device that you wear while you do your usual activities. It measures and records your heart's rhythm and electrical activity. There are different devices that can be used. They can measure your heart's activity for a much longer period of time than a regular ECG.

Your doctor might suggest ambulatory heart monitoring to:

●Look for the cause of symptoms like a racing heartbeat or fainting

●Check for other problems with the heart

●Check for damage to the heart after a heart attack

What device will I have? — This depends on the symptoms you have and how often you have them. There are a few different types of devices:

●Holter monitor – This is a small, portable machine that you wear. It records all of your heart's electrical activity over 1 or 2 days (figure 2). You will have "electrodes" stuck to your chest that are connected to wires leading to the monitor.

●Event monitor – This looks similar to a Holter monitor. But it does not record all of your heart's electrical activity. Instead, it only records your heart rhythm for short periods. It can be worn for up to 30 days.

●Patch monitor – This goes directly on the skin, without wires. It can be worn for up to 30 days. You wear the patch all of the time while you do your usual activities.

●Mobile outpatient cardiac telemetry ("MCOT") – This device records electrical activity for up to 30 days. It has a sensor with 3 electrodes that stick to your chest. The sensor connects to a small, portable monitor.

●Insertable cardiac monitor ("ICM") – This device is inserted under the skin of the chest (figure 3). There are no wires. It can record electrical activity for 2 to 4 years.

Some devices need to be "triggered" to record. This means that if you notice symptoms, you tell the device to start recording. Your doctor or nurse will tell you exactly how your device works.

How do I prepare for ambulatory heart monitoring? — Your doctor or nurse will tell you if you need to do anything special to prepare.

If your device has electrodes that will stick to your chest, you might be asked to:

●Bathe or shower before they are placed

●Trim or shave any hair on your chest

What are the risks of ambulatory heart monitoring? — Your doctor will talk to you about all of the possible risks and answer your questions. Possible risks include:

●Skin irritation from the electrodes, if your device has them

●Bleeding or infection, if you have an insertable monitor

What happens after ambulatory heart monitoring? — Your doctor will look at the information from your monitor. If they do find a problem, they will talk to you about what it means and how to treat it.

If your heart monitor did not show any problems, but you are still having symptoms, you might need more tests.

What else should I know?

●You can do most of your usual activities while wearing the monitor. If there is any activity you're not sure about, check with your doctor or nurse.

●Your doctor might ask you to keep track of your symptoms. To do this, write down the symptom with the date and time that it happened. This way, your doctor can check what your heart was doing at that time. In some cases, your doctor might also want you to keep track of things like when you eat, sleep, exercise, or go to the bathroom.

●If your device has a separate sensor and monitor, follow your doctor's instructions about where to carry or place the monitor. For some devices, you need to carry the monitor with you.

●It might help to wear a loose shirt when wearing a monitor.

●Some devices cannot get wet. This means that you should not shower, bathe, or swim with it. Ask your doctor or nurse whether your device can get wet.

When should I call the doctor? — Call for emergency help right away (in the US and Canara, call 9-1-1) if you think that you might be having a heart attack.

Signs of a heart attack can include (figure 4):

●Severe chest pain, pressure, or discomfort with:

•Breathing trouble, sweating, upset stomach, or cold and clammy skin

•Pain in your arms, back, or jaw

•Worse pain with activity like walking up stairs

●Fast or irregular heartbeat

●Feeling dizzy, faint, or weak

Call your doctor or nurse for advice if you:

●Have any problems with your monitor, such as an electrode coming unstuck or a wire coming loose

●Think that your symptoms are getting worse

More on this topic

Patient education: Insertable cardiac monitor placement (The Basics)
Patient education: Syncope (fainting) (The Basics)
Patient education: Supraventricular tachycardia (SVT) (The Basics)
Patient education: Heart block in children (The Basics)
Patient education: Ventricular premature beats (The Basics)
Patient education: Ventricular tachycardia (The Basics)
Patient education: Sinus node dysfunction (The Basics)
Patient education: Bradycardia (The Basics)
Patient education: Long QT syndrome (The Basics)
Patient education: Atrial fibrillation (The Basics)
Patient education: What can go wrong after a heart attack? (The Basics)

Patient education: Syncope (fainting) (Beyond the Basics)
Patient education: Hypertrophic cardiomyopathy (Beyond the Basics)
Patient education: Atrial fibrillation (Beyond the Basics)
Patient education: Heart attack (Beyond the Basics)