Holter Monitoring: 24 or 48 hours ECG

During a Holter monitoring, the heart's electrical activity is recorded for 24 or 48 hours, with a recording device during a normal daily life. Monitoring is painless and harmless.

The heart is a hollow muscle. The contraction of the heart muscle is in a fixed sequence (phases) and the result of the electrical activity: first the atria of the heart, then the middle wall and finally the ventricles contract.

The ECG shows these different phases of the contraction. For the collection of the electrical activity it is necessary that a series of electrodes are placed on the chest. The electrical activity is captured, recorded and drawn on paper by means of a graphic representation. The result is known as an electrocardiogram (ECG).


Wear comfortable clothing as you present. You can also choose a turtleneck shirt, so patches are not visible. Remove in advance excess hair on the chest. The part of the skin where the electrodes will be applied will be cleaned with alcohol.

The Exam

Please present fifteen minutes before monitoring (to allow possible sweat to dry). The lab technician will ask you to remove your clothing and sit down in a chair or on the examination table. Next the technician will apply three patches (electrodes) on your chest. The patches will be attached to the recording device by means of cables. These cables do not carry electricity. The preparations for the monitoring lasts fifteen minutes.

Back home

Once connected you can return home, with the recording device (Holter Monitor) in a bag around your neck. The lab technician also hands you a diary. Record your activities on the diary. For Example: 09: 00-10 00: breakfast in bed. 10: 00-11: sitting and reading 11.00-12.00: lunch and walk, etc.etc. Stick to your daily routine during the 24 or 48 hours of monitoring. Keep recording while sleeping or at rest.


To shower, bathe, swim or lie on an electric mattress. These actions may damage the equipment or interrupt monitoring.


Do you use medications? If this is the case you can continue taking your medications unless your doctor gives you other indications.

What to do after 24 or 48 hours of monitoring

After monitoring (usually the next morning) you will return the device along with the diary unless you have another agreement with your doctor. In advance you are allowed to detach the device at home.

The results

The lab technician does not give any results or make any statement of the monitoring. For the result you will have to wait for the next appointment with your doctor.