QRS complex
Also written as: QRS — Q-R-S waves
The portion of an ECG representing ventricular depolarization, appearing as a series of upward and downward deflections.
Full Definition
The QRS complex is a critical component of the electrocardiogram that represents the electrical activity associated with ventricular contraction. It consists of three waves: the Q wave (initial downward deflection), R wave (upward deflection), and S wave (downward deflection following the R wave). Normal QRS duration is less than 120 milliseconds, and widening beyond this indicates abnormal ventricular conduction. The morphology and duration of QRS complexes provide essential information for diagnosing arrhythmias, conduction blocks, and determining the origin of abnormal rhythms.
Usage
Usage note: Letters are capitalized and not separated by periods or spaces.
In Context
- "The wide QRS complex suggested ventricular origin of the tachycardia." — ECG interpretation
- "QRS duration was 180 milliseconds, indicating significant intraventricular conduction delay." — Electrophysiology report