What is Holter Monitor / Event Monitor?
A Holter monitor and event monitor are portable devices that record your heart's electrical activity over an extended period—typically 24-48 hours for a Holter monitor or up to 30 days for an event monitor. Unlike a standard ECG that captures just a few seconds of heart activity in the doctor's office, these monitors track your heart rhythm as you go about your daily life. A Holter monitor records continuously, while an event monitor records only when you activate it or when it detects an abnormal rhythm. Both devices are about the size of a small cell phone and are worn on a strap or clipped to your clothing.
Why is it Performed?
Your doctor may prescribe Holter or event monitoring if you're experiencing symptoms that come and go, such as heart palpitations, dizziness, fainting spells, or unexplained fatigue. Since these symptoms might not occur during a brief office visit, extended monitoring increases the chance of capturing the problem when it happens. The test helps diagnose irregular heart rhythms (arrhythmias), assess the effectiveness of heart medications or pacemakers, and determine whether symptoms are related to your heart. Event monitors are particularly useful for symptoms that occur infrequently, perhaps once or twice a week, while Holter monitors work best for daily symptoms.
What to Expect
At your appointment, a technician will attach several small electrode patches to your chest and connect them to the monitoring device with thin wires. You'll wear the monitor continuously during the monitoring period, carrying on with your normal daily activities including work, household tasks, and light exercise. For a Holter monitor, you'll keep a diary of your activities and any symptoms, noting the time they occur. With an event monitor, you'll press a button when you feel symptoms to mark that moment in the recording. You'll return to the office after the monitoring period to have the device removed and the data analyzed. You cannot shower or bathe while wearing the monitor, though you can use a damp cloth for washing.
Preparing for Your Test
No special preparation is needed before your monitoring period begins. Wear comfortable, loose-fitting clothing to your appointment for device placement. Men with significant chest hair may need small areas shaved for proper electrode adhesion. Plan your monitoring period for a time when your symptoms are most likely to occur, and when you can maintain your usual routine. Avoid scheduling the test during periods when you'll be swimming, bathing frequently, or engaging in contact sports. Make sure you understand how to keep your symptom diary or activate your event monitor.
Understanding Your Results
After you return the device, a technician will download and analyze the recording, looking for irregular heart rhythms, pauses, or other abnormalities. Your cardiologist will compare the recording with your symptom diary to see if your symptoms correspond with heart rhythm changes. Normal results show regular heart rhythm throughout the monitoring period with no dangerous arrhythmias. Abnormal findings might reveal atrial fibrillation, premature beats, slow heart rates, or other rhythm disturbances. Based on the results, your doctor may recommend medications, lifestyle changes, or additional testing to address any problems identified.
Have questions about Holter Monitoring or Event Monitoring? Our experienced cardiology team is here to help. Contact Advanced Cardiovascular Specialists & Primary Care at (203) 334-2100 to schedule your appointment or discuss any concerns.
