J wave

They are usually observed in people suffering from hypothermia with a temperature of less than 32 °C (90 °F),[5] though they may also occur in people with very high blood levels of calcium (hypercalcemia), brain injury, vasospastic angina, acute pericarditis, or they could also be a normal variant.

[citation needed] Osborn waves on ECG are frequent during targeted temperature management (TTM) after cardiac arrest, particularly in patients treated with 33 °C.

[6] Osborn waves are not associated with increased risk of ventricular arrhythmia, and may be considered a benign physiological phenomenon, associated with lower mortality in univariable analyses.

[6] The prominent J deflection attributed to hypothermia was first reported in 1938 by Tomaszewski.

These waves were then definitively described in 1953 by John J. Osborn (1917–2014) and were named in his honor.