Hypothermia results in the development of several characteristic electrocardiographic changes. As the core body temperature decreases, several changes in cardiac rhythm occur. Prolongation of the PR, QRS, and QT intervals are also seen. Muscle tremor artifact may be present, even in the absence of clinical shivering. A characteristic secondary deflection on the terminal portion of the QRS complex (Osborn wave) is usually found. All of these features are reversible with rewarming.