Two deaths after prehospital use of adenosine.

Two patients in the prehospital setting died immediately after receiving adenosine for presumed supraventricular tachycardia. Both patients' cardiac rhythms were atrial fibrillation rather than supraventricular tachycardia, and their unstable conditions resulted from underlying diseases-chronic obstructive pulmonary disease and pulmonary embolism-rather than the tachycardia. Misinterpretation of the cause of tachycardia as well as the electrocardiographic findings may be responsible for adverse outcomes.