QRS complex
Also calledQRS · ventricular complex
Definition
The combined deflections produced by ventricular depolarization, made up of the Q, R and S waves. In adults its duration averages about 95 ms (74 to 114 ms in one series of 725 healthy men), and the 2009 AHA/ACCF/HRS recommendations regard more than 110 ms as abnormal: 110 to 119 ms with a typical bundle-branch shape is an incomplete bundle branch block (without that shape, a nonspecific intraventricular conduction delay), and 120 ms or more is wide, seen with complete bundle branch block (when its morphology criteria are also met), nonspecific intraventricular conduction delay, full ventricular pre-excitation and rhythms arising in the ventricles. Its amplitude is normally 5 to 20 mm in the limb leads and 10 to 30 mm in the precordial leads.
Sources
- Surawicz B, Childers R, Deal BJ, Gettes LS. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part III: intraventricular conduction disturbances. Circulation. 2009;119(10):e235-e240. doi.org/10.1161/CIRCULATIONAHA.108.191095
- Samesima N, God EG, Kruse JCL, et al. Brazilian Society of Cardiology guidelines on the analysis and issuance of electrocardiographic reports - 2022. Arq Bras Cardiol. 2022;119(4):638-680. doi.org/10.36660/abc.20220623
- Meek S, Morris F. ABC of clinical electrocardiography. Introduction. II: Basic terminology. BMJ. 2002;324(7335):470-473. doi.org/10.1136/bmj.324.7335.470
Last reviewed 2 October 2026. Every definition in the EKG Dictionary cites the guideline, consensus statement or original paper it comes from.