Correction to QOD 6/6/24: Cases reported to the Toxicology Investigators Consortium between January 1, 2010, and December 31, 2022 were assessed to determine the association with prolonged QRS (>120 ms) and development of seizure, metabolic acidosis, or ventricular dysrhythmia after intoxication with several substances. In patients with nortriptyline ingestion, which outcome did a prolonged QRS predict?
The original answer read: “None. Patients with nortriptyline exposure and a prolonged QRS complex duration did not have statistically different odds ratios of ventricular dysrhythmia, metabolic acidosis, or seizure.” Correction- In fact, the study did report a statistically significant odds ratio of seizure in nortriptyline exposure with prolonged QRS complex duration (OR = 3.6, 95% CI 1.1 – 12.1). The positive and negative predictive values of QRS > 120 ms were 45.0% (95% CI 29.6-61.4%) and 81.6% (95%CI 71.2-88.8%), respectively. The authors found no significant odds ratio for ventricular dysrhythmia, metabolic acidosis, or death. There were notable limitations acknowledged by the authors including small sample size and hard cutoff of QRS>120
Simon M, Kaplan S, Muschler K, Hoyte C, Brent J. The role of QRS complex prolongation in predicting severe toxicity in single-xenobiotic overdose. Clinical Toxicology. 2024;62(1):32-38. https://doi.org/10.1080/15563650.2024.2307356
Contributed by Michael Mullins, MD