QT prolongation and torsades de pointes following sotalol poisoning (ATOM 12)

Abstract

Background: Sotalol is a beta-blocker with potassium channel blocking properties that can cause QT prolongation and torsades de pointes in overdose. We aimed to investigate the electrocardiogram features and complications of sotalol overdoses.Methods: We report a prospective series of adult patients (>15 y) with acute sotalol overdoses >360 mg from July 2015 to May 2025 enrolled through the Australian TOxicology Monitoring collaboration. Data were collected on demographics, ingestion details, clinical features (bradycardia (heart rate <50 bpm), hypotension (systolic <90 mmHg), QT prolongation (QT and heart rate pair plotting above the QT nomogram), torsades de pointes), management, and disposition.Results: There were 31 presentations in 24 patients (12 males, median age 51 years, range: 16-86 years). The median reported dose ingested was 1,440 mg (IQR: 960-2,600 mg, range: 400-14,400 mg). Co-ingestions were taken in 14 (45%) presentations, most commonly ethanol (12, 16%), apixaban (four, 5%) duloxetine and paracetamol (both three, 4%). Bradycardia occurred in 11 (35%, dose range 400-14,400 mg) and hypotension in 10 (32%, dose range 400-14,400 mg). The median QT interval was 520 ms (IQR 460-600 ms, range 360-800 ms), with QT prolongation present in 22 (71%) presentations. Torsades de pointes occurred in four (13%, dose range 2,240-14,400 mg). Nine patients (29%) received inotropes (dose range 960-2,400 mg), most commonly isoprenaline (five, 16%) and high dose insulin (five, 16%). Electrical pacing was performed in three presentations (two had torsades de pointes). One patient was treated with dialysis. The median length of stay was 25.3 hours (IQR 13.5-59.1 hours). There were no deaths.Conclusions: QT prolongation was common, occurring in almost three quarters of patients following sotalol overdose in this series. Four patients developing torsades de pointes taking doses >2,000 mg.