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

What is already known about this subject • Poisoning with β‐blockers can result in cardiovascular and central nervous system effects. • Although much has been reported about metoprolol poisoning's cardiovascular complications, little attention has been paid to acute myocardial infarction (AMI) accompanied by elevated cardiac markers. What this study adds • This case report demonstrates for the first time an association of metoprolol poisoning with acute myocardial infarction in a patient with a previous history of coronary artery disease. • Metoprolol poisoning can induce acute myocardial reinfarction in patients with prior AMI or known coronary artery disease. • In other words, metoprolol overdose can trigger myocardial ischaemia and dysrhythmia in patients with coronary artery disease. Aim To demonstrate that β‐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 percutanerous 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.