Osborne waves in the hot summer.

Osborn waves are produced when the J-point deviates from baseline. While there are many known causes of Osborne waves, hypothermia remains the most common. Previous studies have been inconsistent about the risk of Osborne waves progressing to a deadly arrhythmia. Commonly, once patients are rewarmed, they no longer exhibit Osborne waves or experience cardiac arrhythmias. This patient presented with hypothermia on a hot, humid August day demonstrating two factors known to cause Osborne waves - hypothermia and hypocalcemia. While replenishing the calcium was beneficial, providing ventilator support and active rewarming remained the mainstays of treatment.