Cardiovascular toxicity due to metoprolol poisoning in a patient with coronary artery disease.

Aim: To demonstrate that beta-blocker poisoning results in cardiovascular and central nervous system findings.

Methods: A 56-year-old woman was brought to the emergency department, having been admitted to hospital with 1500 mg of metoprolol ingestion 2 h previously. She had undergone percutaneous transluminal coronary angioplasty and stenting because of acute myocardial infarction (AMI). Her ECG revealed ST segment elevation in inferior leads and junctional dysrhythmia. Her clinical symptoms relieved after pacing and hospitalization and she was discharged.

Results: Our patient demonstrated findings of AMI with hypotension and bradycardia that appeared to result from metoprolol poisoning. Although one patient has been reported to have AMI associated with metoprolol poisoning, our patient is unique with her ECG changes and elevated cardiac markers: this is the first time that AMI characterized by elevated cardiac markers associated with metoprolol toxicity has been reported.

Conclusions: Emergency physicians should bear in mind that AMI can accompany the presentation of metoprolol overdose in those with coronary artery disease. In other words, metoprolol poisoning can trigger myocardial ischaemia and dysrhythmia in those with coronary artery disease.