Holter monitor is a mobile monitoring test that allows the cardiologist to assess a patient’s cardiac rhythm. It is a useful test to investigate palpitations, dizziness, fainting and shortness of breath. It may also be useful in assessing a patient’s risk of dangerous heart rhythms with certain cardiac conditions, eg. following a heart attack or a stroke. 
 
Holter monitor involves the patient carrying a small portable machine (worn with a belt around the waist.  The duration of monitoring depends on the clinical indication and patient type, but may range from 24 hours to 7 days. The cardiologist will discuss this with the patient when organising the test. 
 
During Holter monitor, the patient is able to go to work or perform usual physical activities during the test. The Holter machine is not waterproof, therefore the patient cannot have a shower or swim during the period of monitoring.