24-Hour ECG Monitor, Holter

Continuous recording of your heartbeat to evaluate heart rhythm problems

An ECG is one of the basic and simplest methods used to assess the heart. Electrodes (adhesive plastic patches) are placed on the chest and connected to an ECG machine that records a snapshot of the heart's electrical activity. When a conclusive diagnosis cannot be obtained with a resting ECG and symptoms such as palpitations, dizziness, lightheadedness or blackouts continue, a prolonged ECG recording using the Holter monitor may be necessary.

24-hour ECG monitor continuously records the heart's electrical activity for the whole day or more, making it possible to assess overall heart rate and presence of transient arrhythmias (heart rhythm problems), which may be missed on standard ECG. A heart monitor gives a much better idea of what is happening with the heart rhythm during normal day-to-day activities than a short ECG recording in doctor's surgery. The Holter monitor gives a better chance to capture any abnormal beats or rhythms that may be only intermittent.

The monitor is about the size of a mobile phone and attached to a belt or hung around the neck. You will be asked to keep a diary of any symptoms so that their correlation to recorded ECG is possible. You should go about your normal daily routine with the monitor to get a representative recording of your heart activity.


  • To assess heart rate and rhythm in the presence of fatigue, breathlessness, dizziness and blackouts, which may or may not be related to cardiac problem.
  • To obtain an ECG correlate to palpitations which provides reassurance if the heart rhythm during symptoms is normal or diagnosis and specific treatment if symptoms correspond to an arrhythmia.
  • To assess the level of cardiac risk in certain conditions and situations, e.g. following a heart attack with significant damage to the heart muscle (heart failure), hypertrophic cardiomyopathy (thickened heart muscle)
  • To evaluate chest pain not reproduced with exercise testing
  • To assess the function of an implanted pacemaker
  • To determine the presence or absence of asymptomatic (silent) arrhythmias, e.g. atrial fibrillation after cardioversion (electric shock to normalize heart rhythm) or catheter ablation for complex arrhythmias.


The Holter monitor is a noninvasive test with no known risks. Non-allergic stickers will be used, but rarely some patients may experience transient skin irritation.


The procedure will be explained, and you will be offered the opportunity to ask any questions about the test. The areas where the electrodes are to be placed may need to be shaved. You will be asked to remove all your clothing above the waist, including any underwear. Your privacy will be protected by covering you with a sheet or gown and exposing only the necessary skin. Several sticky pads will be placed onto your chest and attached with wires to the recorder. You may wear the monitor box over the shoulder like a shoulder bag, or you can clip it to your belt or pocket. You will receive instructions regarding how long you will need to wear the recorder (usually 24 to 48 hours). You will be given a diary card to record any symptoms you may have, the time of the symptoms and what you were doing. This is helpful when correlating your symptoms to potential arrhythmias on the ECG monitor. You will also be asked to record your activities throughout the day (i.e. on a walk from 1 to 2.30 pm etc.), when you go to bed, when you get up and what medication you are taking and when. The whole process of attaching the monitor takes approximately 15 minutes.


Once you have been hooked up to the monitor and given instructions, you can return to your usual activities. You should go about your normal routine to obtain a representative recording. If the Holter is indicated for transient problems, it is useful to replicate situations that normally trigger the symptoms to obtain an ECG correlate. You will be instructed to keep a diary of your activities and symptoms, as explained above. Proximity to sources of strong electromagnetic field, such as magnets or metal detectors, may affect the recording quality. Excessive perspiration may cause detachment of the leads.


You must return the monitor the following day. The recording will be played through and analyzed. Dr Ruzicka will discuss the report with you during the follow-up appointment, and depending on the result, appropriate action will be taken. You will be able to resume your normal activities; there is no special care following Holter monitoring.

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