J point
Also calledJ-point · junction point · QRS-ST junction
Definition
The junction where the QRS complex ends and the ST segment begins, at the transition from ventricular depolarization to repolarization. ST-segment elevation or depression is measured at the J point, relative to the isoelectric baseline (usually the PR segment, or the TP segment). J-point elevation of 1 mm or more in two or more adjacent inferior or lateral leads defines the early repolarization pattern, while coved ST-segment elevation of 2 mm or more with T-wave inversion in at least one right precordial lead (V1 or V2) defines the type 1 Brugada pattern.
Clinical noteThresholds for new J-point elevation in two contiguous leads (Fourth Universal Definition of MI): at least 1 mm in every lead except V2 to V3, where it is 2 mm in men 40 and older, 2.5 mm in men under 40 and 1.5 mm in women.
Sources
- Wagner GS, Macfarlane P, Wellens H, et al. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part VI: acute ischemia/infarction. Circulation. 2009;119(10):e262-e270. doi.org/10.1161/CIRCULATIONAHA.108.191098
- Thygesen K, Alpert JS, Jaffe AS, et al. Fourth universal definition of myocardial infarction (2018). Circulation. 2018;138(20):e618-e651. doi.org/10.1161/CIR.0000000000000617
- Zeppenfeld K, Tfelt-Hansen J, de Riva M, et al. 2022 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. Eur Heart J. 2022;43(40):3997-4126. doi.org/10.1093/eurheartj/ehac262
- 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
- Antzelevitch C, Yan GX, Ackerman MJ, et al. J-wave syndromes expert consensus conference report: emerging concepts and gaps in knowledge. Heart Rhythm. 2016;13(10):e295-e324. doi.org/10.1016/j.hrthm.2016.05.024
Last reviewed 2 October 2026. Every definition in the EKG Dictionary cites the guideline, consensus statement or original paper it comes from.