Cardiac monitors are medical devices that continuously track heart rhythm, rate, and electrical activity via ECG electrodes to detect arrhythmias, ischemia, or abnormalities in real-time. Ambulatory types include Holter monitors (24-48hr continuous recording for daily symptoms like dizziness), event monitors (patient-activated for intermittent issues, up to 30 days), and patch recorders (adhesive, wireless 2-week monitoring). Implantable loop recorders (e.g., Reveal LINQ) provide 3+ years of subcutaneous monitoring for syncope via apps. Hospital bedside units display ECG, SpO2, NIBP, respiration with alarms; telemetry enables wireless ward mobility. They analyze P-QRS-T waveforms for AFib, VTach, or bradycardia, guiding therapy like ablation or pacemakers.