MemorialCare Heart & Vascular Institute at:
30-Day Cardiac Event Monitoring30-Day cardiac event monitoring—also known as ambulatory electrocardiography (EKG)—uses a battery-operated, portable device similar to a holter monitor to measure and record the heart’s electrical activity. The monitor is worn during daily activities, and while you sleep. It allows the heart's electrical activity to be recorded intermittently during over a period of 30 days. Event monitoring may be performed to help diagnose abnormal heart rhythms (arrhythmias) or silent myocardial ischemia (a condition where the heart is not receiving enough oxygen-rich blood).