Ambulatory ECG monitoring refers to continuous ECG recording of cardiac rhythms and transient cardiac events over an extended period of time. Types of ambulatory ECG monitoring include continuous ambulatory ECG monitoring, also known as Holter monitoring, event (loop) monitoring, and insertable cardiac monitoring (ICM).

For continuous ECG monitoring, the patient wears a special monitor (Holter) using a loop magnetic tape recording for 24-48 hours or a memory loop battery-operated ECG recorder. Event monitoring is generally used for 2-4 weeks, and recordings are activated by patient trigger when a cardiac event is felt. This type monitoring is beneficial for transient cardiac events. ICM involves implanted monitors that store events automatically according to programmed criteria or when triggered by the patient. ICM is used to evaluate palpitations or syncope of unknown cause.

Ambulatory ECG monitor tracings are used to record onset and termination of rhythm disturbances and to diagnose the cause of dizziness, palpitations, fainting (syncope), lightheadedness, and unexplained fatigue. These procedures are also used to check pacemaker function and automatic implantable defibrillator function status and to trace drug and treatment effectiveness.

1. Holter, 24- to 48-hour ECG monitor:

   1. Prepare the site and apply the leads. Areas may need to be shaved, cleansed with rubbing alcohol, and abraded with gauze.

   2. If and when the patient experiences symptoms, ask the patient to push an indicator marked to save the current ECG tracing. The tracings are transmitted by telephone for analysis.

2. Event ECG monitoring:

   1. Prepare the site appropriately (e.g., shaving, cleansing).

   2. Apply two-channel electrodes, place leads, and connect to the monitor.

   3. Ask the patient to press a record marker when any symptoms (events) occur and also to keep a diary of symptoms.

3. ICM:

   1. Surgically inserted just beneath the skin in the upper chest area.

   2. Following a symptom (e.g., dizziness, fainting spell), a pager-sized device is placed over the implanted monitor to capture and save the data.

   3. Data are then analyzed by the healthcare provider.

1. Abnormal tracings and record may indicate unsuspected disturbances, such as arrhythmias, friction, scratching, and tachycardia (atrial and ventricular).

2. Brachycardia and bradycardia-tachycardia syndrome

3. Premature atrial and bradycardia-tachycardia syndrome

4. Heart blocks

5. Junctional rhythms

6. Flutter or fibrillation

7. Premature atrial or ventricular contractions

8. Hypoxic/ischemic changes

Pretest Patient Care

1. Explain monitoring purpose and procedure. Holter monitor is usually worn for 24-48 hours and then removed. The loop recorders are usually worn for 1-2 weeks and up to 1 month. ICMs can be used for several days up to several months.

2. If the patient experiences symptoms such as dizziness or palpitations, ask the patient to push an indicator and record time of event in a diary.

3. Encourage the patient to continue normal daily events; do not get the recorder wet.

4. Instruct the patient to avoid magnets, metal detectors, high-voltage environments, and electric blankets.

5. An itching sensation under electrodes is common. Instruct patients not to adjust placement sites unless they call in and receive proper procedure.

6. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

1. Incomplete diary or event marker not pushed during symptoms

2. User error

3. Mechanical ineffectiveness

4. Smoking, certain drugs

Normal

• Normal tracings of cardiac ECG sinus rhythms and heart rate

• No hypoxic or ischemic ECG changes