Scenario: These ECG strips are from a 56-year-old man brought to the emergency department after sudden cardiac arrest (SCA). Approximately 7 minutes had elapsed before life support was provided. His initial rhythm was ventricular fibrillation, which returned to sinus rhythm after defibrillation. The patient received routine post-SCA treatment and hypothermia was induced to improve cerebral resuscitation. The top strip was obtained in the emergency department before hypothermia was induced (core temperature, 37.2°C). The bottom strip was obtained in the intensive care unit after several hours of induced hypothermia therapy (core temperature, 33°C).

Interpretation: The top strip shows sinus rhythm with a first-degree atrioventricular block and lengthened QT interval. The bottom strip shows sinus rhythm with first-degree atrioventricular block with J waves indicating hypothermia and lengthened QT interval.

A J wave is clearly seen in the bottom strip between the...

You do not currently have access to this content.