ST-segment elevation myocardial infarction vs. hypothermia-induced electrocardiographic changes: a case report and brief review of the literature.

BACKGROUND: Diagnosed ST-segment elevation myocardial infarction (STEMI) usually prompts rapid cardiac catheterization response.

OBJECTIVE: Our aim was to raise awareness that hypothermia can cause electrocardiographic (ECG) changes that mimic STEMI.

CASE REPORT: Emergency Medical Services (EMS) was called for altered mental status and lethargy in a 47-year-old man with a medical history of paraplegia. His history included hepatitis C, hypertension, seizures, anxiety, and recent pneumonia treated with i.v. antibiotics. When brought in by EMS, the patient was responsive only to painful stimuli. His blood glucose was 89 mg/dL; blood pressure was 80/50 mm Hg, and ECG showed ST elevations diffusely. His vital signs in the emergency department were heart rate 53 beats/min, blood pressure 134/79 mm Hg, respiratory rate 14 breaths/min, pulse oximetry of 100%, and a rectal temperature of 32.7°C (91°F). A second ECG showed diffuse ST elevation, sinus bradycardia with a rate of 56 beats/min, and a first-degree atrioventricular block. J waves were noted in V3-V6, I and II. There were no reciprocal changes or ST depressions. A bedside ultrasound showed no pericardial effusion. The patient underwent cardiac catheterization, which showed no coronary artery disease and a normal ejection fraction. Later, hypercapneic respiratory failure with bilateral pneumonia developed and was intubated. His ECG the following day, once he was rewarmed, showed complete resolution of ST elevation and almost complete resolution of J waves.

CONCLUSION: Obtaining a complete set of vital signs is key to making a correct diagnosis. Hypothermia should be considered in the differential diagnosis of ST elevation.