Early vs. delayed QTc prolongation in acute poisoning: A prognostic accuracy study—A case series

by Amirhossein Shahpar, Amirhossein Mirafzal, Mitra Movahedi, Nazanin Zeinali Nezhad

Given the limited capacity of intensive care units in many countries, it is crucial to identify reliable prognostic markers to optimize poisoning patients management and improve outcomes. This study aimed to assess the predictive value of three variables, namely the initial QTc interval (iQTc) measured within two hours of admission, the delayed QTc interval (dQTc) measured between 6 and 12 hours of entry, and the QTc interval trend over time (ΔQTc), for mortality in patients with undifferentiated poisoning. A retrospective case series was conducted on 70 patients with undifferentiated poisoning admitted to the intensive care unit (ICU) of Afzalipour Hospital between March 21, 2021, and March 20, 2023. The results of the multivariate analysis revealed that dQTc, base deficit, and creatinine were independently associated with mortality (P value < 0.001). The dQTc had the highest predictive ability, with an area under the curve (AUC) of 0.84, followed by ΔQTc with an AUC of 0.76, and iQTc with an AUC of 0.67. Additionally, the results of the Generalized Estimating Equation model with repeated measurements revealed a higher odds ratio for dQTc (OR, 6.33; 95% CI, 2.54–15.79) compared to iQTc (OR, 4.92; 95% CI, 1.71–14.17). The study concluded that monitoring the dQTc interval could provide valuable prognostic information in acute poisoning cases.