Holter Monitor: 24-48 Hour Ambulatory ECG Monitoring

A Holter monitor is a portable, continuous ECG recorder worn for 24-48 hours (up to 14 days with newer patch devices) to detect arrhythmias and correlate symptoms with cardiac rhythm.

How It Works

• 5-7 electrodes on chest → wire to recorder (belt/neck strap) or wireless patch.
• Records every heartbeat; patient keeps symptom/activity diary.
• Data downloaded, analyzed by software + physician review.

Indications

• Palpitations, presyncope/syncope, dizziness.
• Evaluate known arrhythmia burden (AFib, PVCs, SVT).
• Assess antiarrhythmic drug efficacy.
• Post-ablation or post-MI monitoring.
• Cryptogenic stroke workup (prolonged monitoring for AF).

Advantages

• Captures intermittent/asymptomatic arrhythmias missed on 12-lead ECG.
• Correlates symptoms with rhythm (patient-activated event marker).
• Quantifies arrhythmia burden (e.g., % time in AF).

Limitations

• Short window may miss rare events → consider event monitor (30 days) or implantable loop recorder (years).
• Artifacts from movement, poor electrode contact.
• No real-time alerts (unless paired with remote monitoring).

Patient Instructions

• No showering/swimming (unless waterproof patch).
• Avoid electric blankets, high-voltage equipment.
• Continue usual activities; record symptoms with time.