title: The prevalence of long QT interval in post-operative intensive care unit patients.
abstract: The severity of patient illnesses and medication complexity in post-operative critically ill patients increase the risk for a prolonged QT interval. We determined the prevalence of prolonged QTc in surgical intensive care unit (SICU) patients. We performed a prospective cross-sectional study over a 15-month period at a major academic center. SICU pre-admission and admission EKGs, patient demographics, and laboratory values were analyzed. QTc was evaluated as both a continuous and dichotomous outcome (prolonged QTc > 440 ms). 281 patients were included in the study: 92 % (n = 257) post-operative and 8 % (n = 24) non-operative. On pre-admission EKGs, 32 % of the post-operative group and 42 % of the non-operative group had prolonged QTc (p = 0.25); on post-admission EKGs, 67 % of the post-operative group but only 33 % of the non-operative group had prolonged QTc (p < 0.01). The average change in QTc in the post-operative group was +30.7 ms, as compared to +2 ms in the non-operative group (p < 0.01). On multivariable adjustment for long QTc as a dichotomous outcome, pre-admission prolonged QTc (OR 3.93, CI 1.93-8.00) and having had an operative procedure (OR 4.04, CI 1.67-9.83) were associated with developing prolonged QTc. For QTc as a continuous outcome, intra-operative beta-blocker use was associated with a statistically-significant decrease in QTc duration. None of the patients developed a lethal arrhythmia in the ICU. Prolonged QTc is common among post-operative SICU patients (67 %), however lethal arrhythmias are uncommon. The operative experience increases the risk for long QTc.
authors.affiliation: Department of Emergency Medicine, Department of Anesthesiology and Critical Care Medicine, Armstrong Institute for Patient Safety and Quality, Johns Hopkins University School of Medicine, 750 E. Pratt, 15th Floor, Baltimore, MD, 21202, USA. Jpham3@jhmi.edu.
authors.forename: Julius Cuong
authors.initials: JC
authors.lastname: Pham
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Banks
authors.affiliation: Department of Medicine, Columbia University Medical Center, New York, NY, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Narotsky
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Todd
authors.initials: T
authors.lastname: Dorman
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Armstrong Institute for Patient Safety and Quality, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Bradford D
authors.initials: BD
authors.lastname: Winters
mesh_terms: D000328:Adult; D000368:Aged; D003422:Critical Care; D016638:Critical Illness; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008133:Long QT Syndrome / Q000453:epidemiology* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology* / Q000209:etiology; D011184:Postoperative Period; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors
keywords: Arrhythmia; Long QT; Post-operative; Surgical intensive care unit; Torsades de pointes