QTc Prolongation in Pediatric Patients with Diabetic Ketoacidosis

Abstract

Objective: To investigate the association between diabetic ketoacidosis (DKA) and prolonged QTc interval and to assess for correlation between DKA severity and QTc prolongation.

Study design: Retrospective observational study in a pediatric hospital. Patients admitted with DKA diagnosed by laboratory criteria and an electrocardiogram (ECG) performed during a period of acidosis were identified using Looking Glass Clinical Analytics. Data including age, sex, pH, electrolytes, anion gap, and ECG variables were collected. Patients were excluded if they had a prior diagnosis of prolonged QTc or were taking QTc prolonging medications. Severity of DKA was classified as mild (pH 7.24-7.3), moderate (pH 7-7.24), or severe (pH <7). ECGs were read by a pediatric electrophysiologist and QTc interval was manually calculated utilizing the Bazett formula.

Results: Ninety-six patients were included (mean age 15.2 ± 4.2 years, pH 7.12 ± 0.12, bicarbonate 8.6 ± 3.7 mmol/L, potassium 5.3 ± 1.1 mEq/L). Mean QTc interval for all patients in DKA was 454 ± 32 msec. Mean QTc in the mild group was 441 ± 22 msec, moderate group 460 ± 36 msec, and severe group 461 ± 34 msec. There was a significant difference in QTc interval across DKA severity groups (P = .05). There was a significant association between higher anion gaps and greater QTc intervals (r = 0.21, P = .04).

Conclusions: Thirty-one percent of pediatric patients with DKA demonstrated QTc prolongation on ECG. Severity of DKA and worsening acidosis were associated with increased prolongation of the QTc. Further study is required to evaluate the clinical impact of these findings.

Keywords: cardiology; critical care; diabetes mellitus; diabetic ketoacidosis; electrocardiography; pediatrics.