The Holter monitor is a small, portable recorder that records the heart rhythm continuously for 24 hours. The patient is asked to keep a diary of symptoms. This is important because it helps understand if a heart rhythm change is causing symptoms such as dizziness and palpitations.
In patients with atrial fibrillation, Holter monitors are used to evaluate the effectiveness of medications and pacemakers.
For monitoring, electrodes are placed on the chest and connected by wires to the Holter monitor. The monitor is carried by a strap over the shoulder or attached to a belt.