Osborn wave
Synonyms and keywords: camel-hump sign; late delta wave; hathook junction; hypothermic wave; J point wave; K wave; H wave; current of injury; Osborne wave

# Overview
Osborn waves (also known as ) are usually observed on the electrocardiogram of people suffering from hypothermia, though they may also occur in people with high blood levels of calcium (hypercalcemia), brain injury, subarachnoid hemorrhage, damage to sympathetic nerves in the neck, and cardiopulmonary arrest from over sedation, vasospastic angina, or ventricular fibrillation.    

# Historical Perspective
The prominent J deflection attributed to hypothermia was first reported in 1938 by Tomaszewski. The wave was observed by others, including Kossmann, Grosse-Brockhoff and Schoedel, Bigelow et al, Juvenelle et al, and Osborn.    
Over the years, the unusual wave has increasingly been called an Osborn wave, probably because of Osborn's excellent descriptive article written in 1953. Clinicians labeled the deflection an Osborn wave in honor of Osborn, one of the first American Heart Association research fellows.  

# Causes

## Common Causes
- Hypothermia

## Causes of Osborn Waves in Alphabetical Order
- Cerebrovascular accident 
- Coronary vasospasm
- Damage to sympathetic nerve chain in the neck after radical neck dissection 
- Hypercalcemia
- Hypothermia
- Subarachnoid hemorrhage
- Ventricular fibrillation, immediately before and after, often in the setting of vasospastic angina

# Diagnosis

## Electrocardiogram
The most typical finding is the appearance of the Osborne J wave, an extra deflection between the QRS complex and the T wave.  Osborn waves are positive deflections occurring at the junction between the QRS complex and the ST segment, where the S point, also known as the J joint, has a myocardial infarction-like elevation.  Osborn waves are more prominent in the left precordial leads.  They increases in size with decreasing temperature.  They are caused by a current of injury, delayed ventricular depolarization, or early repolarization.
Osborn waves may first appear on the ECG for temperatures less tahn 91.4 degrees Fahrenheit (33 degrees Celsius), and consistently appear when when the temperature falls below 25 degrees Centigrade.
There is variability in the morphology of Osborn waves as all J wave deflections do not look alike.  Some Osborn waves are merely elevations of ST segments in leads V1 and V2, whereas others are of the "spike-and-dome" variety.  Given the variability in morphology, a variety of mechanisms may be responsible for the size and shape of J wave deflections.
Shown below is an example of the "spike and dome" variant of the Osborn wave:
Shown below is an Osborn wave in an 81-year-old male with a core temperature 89.5 degrees F (31.94 C):

## Electrocardiographic Examples

### Examples of Osborn Waves in the Setting of Hypothermia
Shown below is the 12 lead ECG of a patient with a body temperature of 32 degrees Celsius. Note the sinus bradycardia, the prolonged QT interval (QTc is not prolonged) and the Osborn J wave, most prominently in leads V2-V5:
Shown below is An ECG of a patient with a body temperature of 28 degrees Celsius:
Shown below are Osborn J waves due to hypothermia:
Shown below are Osborn J waves due to hypothermia:

### Example of Osborn Waves in the Setting of Vasospastic Angina
Shown below is the time course of twelve-lead ECG in a 52-year-old man with vasospastic angina. ECGs were obtained prior to the ischemic attack (A), at the onset of chest pressure (B), immediately before ventricular fibrillation (C), after defibrillation and administration of intravenous lidocaine and magnesium (D), and 2 days after the episode (E). Osborn waves (arrowheads) were best seen in the inferior and lateral leads around the occurrence of ventricular fibrillation. In contrast to hypothermic patients, the tracing shows sinus tachycardia and short QT intervals.