Zolpidem Intoxication Associated with Probable Reverse Stress-Induced Cardiomyopathy and QT Prolongation: A Case Report

Zolpidem is a widely prescribed non-benzodiazepine hypnotic. A 49-year-old woman presented to the emergency department with altered mental status after intentional ingestion of approximately 300 mg of zolpidem; the blood zolpidem concentration was 674 µg/L approximately 8 h after ingestion. The initial ECG already showed QTc prolongation (499 ms). She developed chest discomfort and modest high-sensitivity troponin T elevation, and echocardiography showed transient left ventricular dysfunction (ejection fraction 42%) with basal-to-mid regional wall motion abnormalities and relative apical sparing, suggestive of probable reverse stress-induced cardiomyopathy. Coronary computed tomography angiography showed no coronary plaque or significant stenosis. On hospital day 2, telemetry captured a brief monomorphic ventricular run and QTc later peaked at 681 ms. Follow-up echocardiography on hospital day 5 showed recovery of left ventricular systolic function (LVEF 60%) and resolution of the regional wall motion abnormalities. These findings cannot be attributed solely to zolpidem. Stress may have contributed to the cardiomyopathy. Mild hypokalemia and left ventricular dysfunction may have reduced repolarization reserve. The peak QTc occurred after blood zolpidem concentrations had substantially decreased and may have reflected evolving stress-induced cardiomyopathy or concurrent exposure to cardiovascular medications. Cardiac evaluation and continuous monitoring should be considered when zolpidem intoxication is accompanied by cardiac symptoms, biomarker elevation, or ECG abnormalities.