electrogram

Full Definition

An electrogram (EGM) is an intracardiac electrical signal recorded directly from electrodes positioned within the heart chambers or on the cardiac surface during electrophysiology procedures. Unlike surface ECGs, electrograms provide high-resolution local electrical activity that helps identify arrhythmia mechanisms, mapping abnormal circuits, and guiding ablation therapy. They are essential for precise diagnosis of complex arrhythmias and real-time monitoring during interventional procedures.

Usage

Usage note: Often abbreviated as EGM in clinical documentation. Distinguish from surface electrocardiogram (ECG/EKG).

In Context

• "The electrogram showed fragmented signals consistent with scar-related ventricular tachycardia." — EP study report
• "High-density mapping revealed abnormal electrograms in the left atrial posterior wall." — Ablation procedure note