Prolongation of QRS duration (prolonged QRS) is associated with severe outcomes in non-tricyclic antidepressant poisoning. However, factors other than xenobiotics affecting QRS duration have not yet been investigated. Hence, this study aimed to identify factors contributing to prolonged QRS. This study was a single-center retrospective case control study. Patients who had overdosed on drugs or orally ingested xenobiotics that they would not normally ingest orally were included in the study. Patients were divided into two groups: prolonged QRS and normal QRS. Subsequently, these groups were compared. We performed a logistic regression analysis with the factors extracted by comparison as explanatory variables and prolonged QRS as the objective variable. In total, 108 patients were analyzed
19 belonged to the prolonged QRS group. In the prolonged QRS group, factors such as male sex, low level of potassium, and xenobiotic ingestion resulted in prolonged QRS. In a logistic regression analysis, significant differences were observed in terms of male sex (odds ratio [OR], 27.00
95% confidence interval [CI], 5.93-123.00
p<
0.002), xenobiotics ingested that resulted in prolonged QRS (OR, 8.55
95% CI, 1.84-39.70
p<
0.002), and potassium levels (OR, 0.15
95% CI, 0.03-0.88
p=0.035). Ingestion of sodium channel blockers, male sex, and low level of potassium may contribute to prolonged QRS.