Prolonged QT interval corrected for heart rate during diabetic ketoacidosis in children.

OBJECTIVE: To evaluate the effect of diabetic ketoacidosis (DKA) on the QT interval corrected for heart rate (QTc) in children. Ketosis occurs in several conditions, including DKA and alcoholic ketoacidosis, and during use of very low-carbohydrate diets. Prolongation of the QTc has been described in a few children receiving ketogenic diets, but cardiac effects of ketosis have not otherwise been investigated.

DESIGN: For this observational study, we performed electrocardiography during DKA and after recovery. We measured QTc as the QT interval divided by the square root of the R-R interval and correlated QTc with clinical variables.

SETTING: The pediatric emergency department and intensive care unit of an academic medical center.

PATIENTS: Thirty children with type 1 diabetes mellitus and DKA.

MAIN OUTCOME MEASURE: The QTc during DKA.

RESULTS: The mean (SD) QTc during DKA was 450 (38) milliseconds (range, 378-539 milliseconds). After recovery from DKA, the mean (SD) QTc decreased to 407 (36) milliseconds (range, 302-485 milliseconds; difference, 43 milliseconds; 95% confidence interval, 23-63 milliseconds) (P < .001). Fourteen of the 30 children (47%) had prolonged QTc during DKA (range, 450-539 milliseconds). After recovery from DKA, only 4 children (13%) had persistent QTc prolongation (range, 451-485 milliseconds). The anion gap was significantly associated with QTc prolongation (correlation coefficient, 0.49; P = .006). Most patients had no electrolyte abnormalities or hypoglycemia to account for QTc prolongation.

CONCLUSIONS: Prolonged QTc occurs frequently during DKA and is correlated with ketosis. Current guidelines regarding cardiac monitoring of children during DKA should be strictly followed, and electrocardiographic screening of patients with other ketotic conditions should be considered.