An ECG Machine is a Class II medical device that records and displays the electrical activity of the heart through surface electrodes, producing an electrocardiogram for diagnosis of cardiac conditions. Standard diagnostic machines record 12 simultaneous leads (3 limb, 6 precordial, 1 ground) with frequency response 0.05-150 Hz, sampling rate 500-1,000 Hz, and high-resolution (5-10 µV) signal acquisition. Features include color touchscreen display, thermal array printer, computerized interpretation algorithms, internal memory (50-500+ ECGs), and network connectivity for EMR integration. Lead wires (AHA or IEC color coding) connect to disposable adhesive electrodes. Portable models (5-15 kg) with rechargeable batteries enable bedside and mobile use; cart-mounted units provide full diagnostic capability. Primary clinical applications include diagnosis of arrhythmias (AF, VT, bradycardia), detection of myocardial ischemia/infarction (STEMI, NSTEMI), evaluation of chest pain, preoperative cardiac risk assessment, monitoring electrolyte imbalances, assessment of chamber enlargement, and drug effect/toxicity monitoring. Essential diagnostic equipment in emergency departments, cardiology clinics, ICUs, operating rooms, and primary care settings worldwide.