Drug-induced QTc-interval prolongation in the intensive care unit: Incidence and predictors

Tien M.H. Ng, Keith M. Olsen, Megan A. McCartan, Susan E. Puumala, Katie M. Speidel, Melissa A. Miller, Tom D. Sears

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


There is a paucity of information regarding QTc prolongation in critically ill patients. A prospective observational study was conducted to assess the incidence and predictors of QTc prolongation associated with medications in intensive care unit (ICU) patients. Consecutive adult patients prescribed prespecified QTc-prolonging medications were assessed for development of the combined incidence of QTc >500 ms at anytime and QTc increase >60 ms above baseline. Over 3 months, 200 consecutive patients (63 ± 18 years; 52% female; 73% Caucasian; baseline QTc 447.3 ± 51.5 ms) were evaluated. The primary end point occurred in 48% of the patients (QTc >500 ms 40%, QTc increase >60 ms 29%). The majority of patients experienced a QTc >470 or 450 ms (60.5%). Mean increase in QTc at 48 hours was 20 ± 35 ms. Upon multivariate analysis, length of stay [odds ratio 1.30, 95% confidence interval (1.15, 1.47)] and baseline QTc [1.01 (1.01, 1.02)] were associated with an increased risk for the primary end point, while beta-blockers [0.41 (0.20, 0.81)] were associated with a risk reduction. In conclusion, increased risk of proarrhythmia, as assessed by QTc prolongation, occurs in the majority of ICU patients when prescribed medications with electrophysiologic properties. Increased vigilance is warranted. The possible protective effect of beta-blockers requires confirmation.

Original languageEnglish (US)
Pages (from-to)19-24
Number of pages6
JournalJournal of Pharmacy Practice
Issue number1
StatePublished - 2010


  • Arrhythmia
  • Critical care
  • Drug therapy
  • Drug toxicity
  • Intensive care
  • Torsade de pointes

ASJC Scopus subject areas

  • Pharmacology (medical)


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