See [bookends: Electrocardiographic Early Repolarization: A Scientific Statement From the American Heart Association.](bookends://sonnysoftware.com/ref/DL/279985) > *Osborn wave* (j wave) is a positive deflection seen at the J point in precordial and true limb leads. Most commonly a/w [[Hypothermia]]. Changes appear as a reciprocal, negative deflection in v1 and aVR ![[Pasted image 20241112161201.png|osborn waves of hypothermia. Not much shivering artefact in this ECG, perhaps because temp is < 32 deg (often the threshold for which osborn waves begin to appear)]] ![[Pasted image 20240326000901.png]] J point in a) normal; b) J point elevation; c) with Osborn wave (J wave); d) J point depression > _Note_: The letter J on the ECG defines 2 totally different and unrelated events. The **J point** is a point in time marking the end of the QRS and the onset of the ST segment present on all ECGs. The **J wave** is a much less common, slow deflection of uncertain origin originally described in relation to hypothermia. **Differences from epsilon wave** epsilon wave is a part of the QRS due to [[Syncope ECG patterns#ARVC]], rather than distinct wave from QRS ![[ARVC-epsilon-wave.png.png]] # Causes - [[Hypothermia]] - [[hypercalcaemia]] - LVH - takotsubo cardiomyopathy - Normal variant and [[STEMI mimics#Benign Early Repolarisation]] - [[Subarachnoid haemorrhage|SAH]] - [[Syncope ECG patterns|Brugada]]