24-Hour Electrocardiography (Holter Monitoring)

A 24-hour electrocardiogram, commonly called a Holter monitor, continuously records the heart’s electrical activity for one or more days. It is used when a standard ECG does not capture intermittent symptoms such as palpitations, dizziness, fainting, or unexplained chest pain. It helps detect arrhythmias, evaluate pacemaker function, and monitor treatment effectiveness.

• No fasting or special dietary changes are needed.
• Shower before the monitor is applied, as you must avoid bathing or swimming during the monitoring period.
• Wear loose-fitting clothing for easier placement of electrodes and to conceal the monitor.
• Keep a symptom diary, noting the time of any chest discomfort, palpitations, dizziness, or other relevant symptoms.

Several small adhesive electrodes will be placed on your chest and connected to a portable recording device, usually worn on a belt or shoulder strap. You will go about your normal daily activities, except for bathing, swimming, or contact sports. The device records continuously for 24–48 hours. Afterward, the monitor is returned, and the data is analyzed.

• The test is painless and safe.
• Mild skin irritation or rash may occur at the electrode sites.
• In rare cases, adhesive sensitivity may require electrode adjustment.

A cardiologist reviews the continuous recording to detect abnormal rhythms or electrical changes. The data is compared with your symptom diary to determine whether episodes correlate with ECG findings. Results guide further management, which may include medication adjustments, electrophysiology testing, or pacemaker/defibrillator consideration.