ECG Challenge: A Post–Cardiac Arrest Pattern

Philip J. Podrid, MD


December 20, 2019

The correct diagnosis is normal sinus rhythm, Osborn waves, also called J waves (Figure 2).

Figure 2. Courtesy of Dr Podrid.


The rhythm is regular at a rate of 60 bpm. There is a P wave before each QRS complex (+) with a stable PR interval (0.20 sec). The P wave is positive in leads I, II, aVF, and V4-V6. Therefore, this is a normal sinus rhythm.

The QRS complex has a normal duration (0.08 sec) and morphology. The axis is normal between 0° and +90° (positive QRS complex in leads I and aVF). A prominent elevated J point (↓) follows the QRS complex. This is termed an Osborn or J wave, and it is the result of hypothermia.

Hypothermia may occur after exposure to cold, inadequate warming after cardiac surgery, or cooling after a cardiac arrest, as in this case. The height of the Osborn wave correlates with temperature (the lower the temperature the taller the Osborn wave) and it resolves with warming. It is not associated with arrhythmia or other electrophysiologic abnormalities.


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