ECG Changes in Patients with Hypothermia

Abstract

Introduction: Hypothermia is defined as a condition, in which the body core temperature is below 35°C. The most common causes are due to environmental circumstances, e.g. exposure to cold weather. Non-environmental causes are uncommon, but also should be taken into consideration, e.g. hypothermia with diabetic ketoacidosis. Our aim is to draw attention to the changes in the electrocardiogram (ECG), which are characteristic for the patients with hypothermia. Materials and Methods: We conducted a literature review using Pub Med, Google Scholar, and MedlinePlus databases from 1984 until March 2016. We used keywords like hypothermia, ECG in hypothermia, cases of hypothermia and accidental hypothermia. We included reviews published in journals with evidence-based medical publications. Results: In a normal 12-lead ECG obtained from a hypothermic patient, a broad spectrum of changes can be observed, they could be confusing and necessitating some extra tests and exams. Some of them may seem similar to those found in acute coronary ischaemia and pericarditis. The T wave can show varied differences, e.g. the T wave can be negative in lead V2-V6. PR, QT and QRS intervals can be differently prolonged. Most specific for hypothermia is the J point elevation, also called Osborne wave, an extra elevation after the QRS complex. The wave correlates directly with the body temperature, the amplitude increases with the decreasing temperature. Hypothermic patients may present with different atrial or ventricle rhythm disorders. Bradyarrhythmias are typical of those patients incl. atrial fibrillation with slow ventricular response, varying degrees of AV block, etc. All ECG changes disappear after rewarming the patients. Conclusion: Hypothermia often results in ECG changes, and should be recognised by the emergency doctors, because they have a diagnostic and prognostic importance. The special findings should be detected as early as possible to provide patients the correct treatment.