The dynamic nature of ST-segment and T-wave changes during acute MI

Obtaining a prehospital 12-lead electrocardiogram (ECG) diagnostic of acute myocardial injury has been demonstrated to hasten the administration of thrombolytic agents in the emergency department. This case demonstrates that a prehospital electrocardiogram diagnostic of acute anterior wall infarction can become non-diagnostic following routine administration of oxygen, nitroglycerin, and morphine by paramedics. Although this phenomenon has been observed in the in-hospital setting, it has not been reported in patients with a prehospital ECG.