Holter ECG or ambulatory blood pressure monitoring: what each test shows

A patient often tells me, “I have worn a Holter and it was normal.” My first question is: a Holter ECG or a blood pressure monitor?

Although we use the same word, these are two very different tests.

A Holter ECG continuously records the heart’s electrical activity, usually for 24 hours or longer. We use it to investigate palpitations, extra beats, episodes of rapid heartbeat, dizziness or fainting, and arrhythmias that may not appear on a standard ECG.

Ambulatory blood pressure monitoring measures blood pressure at regular intervals during the day and night. It helps when home and clinic measurements differ, when white-coat or masked hypertension is suspected, and when we want to assess whether treatment covers the full 24 hours.

One test cannot replace the other. In both cases, it is useful to bring the complete report to your appointment, rather than only saying that it was normal.