• Hypothermia
• ECG and Hypothermia
• Osborn Wave and Hypothermia

Hypothermia

• Hypothermia (Cooling)
• is a decrease in core body temperature < 35°C.
• The core body is considered to be the internal organs, primarily the liver
• Metabolism slows down throughout the body
• The individual phases of the action potential are prolonged
• Conduction through the conduction system slows down

Osborn Wave and Hypothermia

• The most common cause of Osborn wave (J wave) is hypothermia < 32°C
• Amplitude and width increase with worsening hypothermia
• After correction of hypothermia, the Osborn wave may persist for 12-24 hours.
• Each Osborn wave is a risk factor for ventricular tachycardia (Le syndrome d’Haïssaguerre)
• Ventricular tachycardia most commonly occurs during warming of the body at 28-32°C
  
  
• Osborn wave correlates with hypothermia differently in each patient

Hypothermia (34°C)

• Osborn Wave is Smaller
• Prolonged QT Interval
• Corrected QT interval (504ms)
• Sinus Bradycardia
• Heart Rate < 50/min.

Hypothermia (36°C)

• Osborn wave at 36°C has nearly disappeared
• Borderline prolonged QT interval
• Corrected QT interval: (462ms)
• Bradycardia is no longer present
• Heart rate 55/min.

Hypothermia (36°C)

• Sinoatrial bradycardia (30/min.)
• No Osborn waves or Tremor artifact present

Hypothermia (27°C)

• Huge Osborn waves (V2-6, I, II, III, aVF)
• Atrial fibrillation
• Prolonged QT interval (0.6s)

Rapid Onset Hypothermia (31°C)

• Sinus Tachycardia
• Frequency > 100/min.
• At the onset of hypothermia, tachycardia is present; bradycardia develops later
• Therefore, bradycardia is not yet present on this ECG
• Osborn Waves (V2-6)
• Prolonged QT Interval (0.5s)
• Positional (Shivering) Artifact
• Shivering muscles from the cold create electrical impulses that obscure the heart impulses

Hypothermia (32°C)

• Sinus Bradycardia (49/min.)
• AV Block I Degree (prolonged PQ interval 0.36s)
• Osborn Waves (In all leads)
• The patient was hypothermic upon arrival at the hospital, and the body temperature started to gradually rise:

Hypothermia (35°C)

• Osborn Waves are smaller

Hypothermia (36°C)

• Osborn Waves have almost disappeared