elektrokardiografie

Elektrokardiografie, commonly known as electrocardiography (ECG or EKG), is a non-invasive diagnostic method that records the electrical activity of the heart. Electrodes placed on the chest and limbs detect small voltage changes produced by cardiac depolarization and repolarization, and a recorder or computer plots these signals as a time-varying waveform.

The standard 12-lead ECG provides multiple viewpoints of cardiac electrical activity, enabling assessment of heart rate and rhythm, conduction intervals such as PR, QRS duration, and QT interval, and patterns that may indicate ischemia, infarction, chamber enlargement, electrolyte disturbances, or other cardiac conditions. The P wave, QRS complex, and T wave reflect atrial depolarization, ventricular depolarization, and ventricular repolarization, respectively.

Clinical use includes evaluation of chest pain, syncope, palpitations, electrolyte disturbances, and perioperative risk, as well as monitoring of known heart disease and during stress testing. Ambulatory ECG techniques, such as Holter monitoring (24–48 hours) and event recorders, extend observation over longer periods to capture intermittent arrhythmias.

Safety and interpretation: ECG is non-invasive with minimal risk, though skin irritation from electrodes and movement artifacts can affect recordings. Accurate electrode placement and trained interpretation are essential, as a single tracing may not detect all conditions. Historically, electrocardiography was developed by Willem Einthoven in the early 1900s, and the 12-lead system remains standard in modern practice.