Patient Guide

24-Hour Ambulatory Blood Pressure Monitoring

What Is a 24-hour Ambulatory Blood Pressure Monitoring Test?

Blood pressure varies with the time of the day, one's psychological state and the level of physical activity. Blood pressure readings are frequently higher when you see your doctor in the clinic than when you are at home, especially if you are anxious.

Ambulatory blood pressure monitoring is a test where your blood pressure is measured at multiple intervals over a period of 24 hours. You will be required to bring a portable computerised blood pressure recorder around for the entire test duration. This test provides more information than just a single blood pressure reading in the clinic which allows your doctor to better understand the pattern of your blood pressure throughout the day.

Why Do I Need This Test?

Ambulatory blood pressure monitoring is particularly useful in the evaluation of mild hypertension. This condition is commonly over-diagnosed based on clinic blood pressure readings alone. It is also used to study the effects of blood pressure-lowering medications, detect excessive blood pressure swings, and to check for severe hypertension.

Without accurate diagnosis and appropriate treatment, high blood pressure can damage the heart, kidneys, brain, eyes and blood vessels.

What Can I Expect for the Test?

A blood pressure cuff will be attached to one of your arms, and connected to a portable computerised blood pressure recorder usually worn at your waist for 24 hours. The recorder will then measure blood pressure at pre-set intervals throughout a 24-hour period. Setting up the test equipment generally takes less than 20 to 30 minutes in the Non-Invasive Cardiac Laboratory.

  1. As the procedure is done on an outpatient basis, once the recorder is fitted, you can leave the hospital and carry on with your usual activities, except that you should not bathe, swim or engage in activities that will wet the equipment. Avoid big movements of the arm and areas attached with the parts of the equipment.
  2. You should not engage in vigorous sports that may damage the recorder, or tamper with any part of the instrument assembly. For maximum accuracy, keep your arm as straight and relaxed as possible during the cuff inflation and deflation.
  3. The cardiac technologist fitting your recorder will provide you with a diary sheet to record your activities and any symptoms you may experience during the test. Accurate interpretation of your ambulatory blood pressure recording depends on the detailed recordings in your diary.
  4. On your return to the hospital the following day, the recorder will be removed and the data will be transferred to the computer for analysis.

Preparing for a 24-hour Ambulatory Blood Pressure Monitoring Test

On the day of the test, have a bath before coming in loose clothing to our Non-Invasive Cardiac Laboratory.

Ladies are advised to come in a two-piece blouse and skirt/pants outfit.

What Are the Potential Risks?

There are no major side effects associated with this test. However, you may experience the following:

  • Some discomfort on the arm when the cuff inflates
  • Mild rash at the site of cuff

Please inform the cardiac technologist or the doctor should you experience these problems.

When Will I Know the Results?

The results and the next step of your treatment will be discussed at the next outpatient clinic appointment with your doctor.

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