Frequency of cardiotoxicity following intramuscular administration of epinephrine in emergency department patients with anaphylaxis.

Objectives: Epinephrine can be a life-saving treatment for patients with anaphylaxis. Potential cardiovascular side effects of epinephrine may contribute to clinician hesitancy to use it. However, the frequency of cardiotoxicity resulting from epinephrine treatment for anaphylaxis is not well described. We sought to describe the frequency of cardiotoxicity following intramuscular (IM) administration of epinephrine in adult emergency department (ED) patients with anaphylaxis. Methods: We conducted a retrospective observational study at a single, quaternary care academic ED in Tennessee. We identified consecutive ED visits with the diagnosis of anaphylaxis from 2017 to 2021 who received at least one intramuscular (IM) dose of epinephrine in the ED. Analysis was primarily descriptive. The primary outcome was cardiotoxicity, the occurrence of any of the following after epinephrine administration: ischemic electrocardiogram changes, systolic blood pressure >200 mmHg, or cardiac arrest ≤4 h; elevated troponin ≤12 h; or percutaneous coronary intervention or depressed ejection fraction ≤72 h. Results: Among 338 included patients, 16 (4.7%; 95%CI: 2.8-7.6%) experienced cardiotoxicity. Cardiotoxic events included eight (2.4%) ischemic electrocardiogram changes, six (1.8%) episodes of elevated troponin, five (1.5%) atrial arrhythmias, one (0.3%) ventricular arrythmia, and one (0.3%) depressed ejection fraction. Patients with cardiotoxicity were significantly older, had more comorbidities, and were more likely to have received multiple doses of epinephrine or an epinephrine infusion compared with a single IM dose of epinephrine. Conclusions: Among 338 consecutive adult ED patients who received IM epinephrine for anaphylaxis during a recent 4-year period, cardiotoxic side effects were observed in approximately 5% of patients.