PR interval
Also calledPR · P-R interval · PQ interval
Definition
The time from the onset of the P wave to the onset of the QRS complex, whether the first QRS deflection is a Q or an R wave. It covers atrial activation plus the physiological delay in the AV junction and the His-Purkinje system. Global measurement across simultaneously recorded leads, from the earliest onset, is preferred, because a single lead tends to underestimate it. The normal adult range is 120 to 200 ms, varying with heart rate and age. A PR above 200 ms is first-degree AV block, and a PR below 120 ms is seen with ventricular pre-excitation and with junctional or other ectopic atrial rhythms.
Sources
- Kligfield P, Gettes LS, Bailey JJ, et al. Recommendations for the standardization and interpretation of the electrocardiogram: part I: the electrocardiogram and its technology. Circulation. 2007;115(10):1306-1324. doi.org/10.1161/CIRCULATIONAHA.106.180200
- 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
- Kusumoto FM, Schoenfeld MH, Barrett C, et al. 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay. Circulation. 2019;140(8):e382-e482. doi.org/10.1161/CIR.0000000000000628
- 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.