QRSkompleks

QRSkompleks, known in English as the QRS complex, is the portion of the electrocardiogram (ECG) that corresponds to ventricular depolarization. It appears after the P wave and before the T wave. In a standard 12-lead ECG, it typically comprises a small Q wave, a large upward R wave, and a downward S wave, but its precise shape varies with lead orientation and individual anatomy.

Duration and conduction: The QRS complex usually lasts 0.06–0.10 seconds (60–100 ms) in healthy adults; values above 0.12 seconds indicate a prolonged ventricular conduction time. A narrow QRS reflects rapid conduction through the His-Purkinje system, while widening may indicate bundle branch block, ventricular ectopy, or intraventricular conduction delay.

Axis and morphology: The direction of ventricular depolarization is summarized by the QRS axis, normally between -30° and +90°. Abnormal axis or unusual QRS morphology can signal structural heart disease or conduction disturbances.

Clinical significance: Evaluation of the QRS complex helps identify prior myocardial infarction via pathologic Q waves, ventricular hypertrophy, arrhythmias, or pre-excitation patterns. In combination with other ECG features, QRS analysis supports diagnosis and monitoring of cardiac conditions.

Overview: The QRS kompleks is a central component of the ECG, reflecting the rapid electrical activation of the ventricles and contributing to the interpretation of cardiac rhythm and conduction.