QTc prolongation indicates a poor prognosis in patients with organophosphate poisoning.

This study reviewed emergency department electrocardiograms of 223 patients with organophosphate poisoning from January 1982 to June 1994: 97 (43.5%) had QTc prolongation and were placed in group A; 126 patients without QTc prolongation were designated as group B. Compared with group B, group A patients had a higher mortality (19.6% v 4.8%, P < .001) and a higher incidence of respiratory failure (56.7% v 20.6%, P < .001). Serum cholinesterase levels were determined in the 223 patients: 92 (41.3%) were classified as severe poisoning. 32 (14.3%) as moderate, 41 (18.1%) as mild, and 58 (25.7%) as very mild. The severe group had a high incidence of QTc prolongation (P < .001), a high incidence of respiratory failure (P < 0.001), and a higher mortality rate (P < 0.001) than the other groups. Of the QTc prolongation patients, 59.8% (55/92) had a high incidence of respiratory failure (78.2% v 35.1%, P < .0001) and a higher mortality rate (29.1% v 8.1%, P < 0.05) compared with 40.2% (37/92) of the patients without QTc prolongation in the severe group. In conclusion, a complete electrocardiogram at the emergency department is important and of prognostic value.