title: ECG changes on continuous telemetry preceding in-hospital cardiac arrests.
abstract: BACKGROUND
  About 200,000 patients suffer from in-hospital cardiac arrest (IHCA) annually. Identification of at-risk patients is key to improving outcomes. The use of continuous ECG monitoring in identifying patients at risk for developing IHCA has not been studied.
  
  
  OBJECTIVE
  To describe the profile and timing of ECG changes prior to IHCA.
  
  
  METHODS
  Retrospective, observational.
  
  
  METHODS
  Single 520-bed tertiary care hospital.
  
  
  METHODS
  IHCA in adults between April 2010 and March 2012 with at least 3 hours of continuous telemetry data immediately prior to IHCA.
  
  
  METHODS
  We evaluated up to 24 hours of telemetry data preceding IHCA for changes in PR, QRS, ST segment, arrhythmias, and QTc in ventricular tachycardia cases. We determined mechanism and likely clinical cause of the arrest by chart and telemetry review.
  
  
  RESULTS
  We studied 81 IHCA patients, in whom the mechanism was ventricular tachycardia/fibrillation in 14 (18%), bradyasystolic in 21 (26%), and pulseless electrical activity (PEA) in 46 (56%). Preceding ECG changes were ST segment changes (31% of cases), atrial tachyarrhythmias (21%), bradyarrhythmias (28%), P wave axis change (21%),QRS prolongation (19%), PR prolongation (17%), isorhythmic dissociation (14%), nonsustained ventricular tachycardia (6%), and PR shortening (5%). At least one of these was present in 77% of all cases, and in 89% of IHCA caused by respiratory or multiorgan failure. Bradyarrhythmias were primarily seen with IHCA in the setting of respiratory or multiorgan failure, and PR and QRS prolongation with IHCA and concomitant multiorgan failure.
  
  
  CONCLUSIONS
  This is a retrospective study with a limited number of cases; each patient serves as their own control, and a separate control population has not yet been studied.
  
  
  CONCLUSIONS
  ECG changes are commonly seen preceding IHCA, and have a pathophysiologic basis. Automated detection methods for ECG changes could potentially be used to better identify patients at risk for IHCA.
authors.affiliation: Cardiac Arrhythmia Center, David Geffen School of Medicine at University of California, Los Angeles, CA.
authors.forename: Duc H
authors.initials: DH
authors.lastname: Do
authors.affiliation: Cardiac Arrhythmia Center, David Geffen School of Medicine at University of California, Los Angeles, CA.
authors.forename: Justin
authors.initials: J
authors.lastname: Hayase
authors.affiliation: Cardiac Arrhythmia Center, David Geffen School of Medicine at University of California, Los Angeles, CA.
authors.forename: Ricardo Dahmer
authors.initials: RD
authors.lastname: Tiecher
authors.affiliation: Biomedical Engineering Graduate Program, Henry Samueli School of Engineering and Applied Science, University of California, Los Angeles, CA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Department of Physiological Nursing, School of Nursing, University of California, San Francisco, CA; Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA.
authors.forename: Xiao
authors.initials: X
authors.lastname: Hu
authors.affiliation: Cardiac Arrhythmia Center, David Geffen School of Medicine at University of California, Los Angeles, CA. Electronic address: nboyle@mednet.ucla.edu.
authors.forename: Noel G
authors.initials: NG
authors.lastname: Boyle
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000401:mortality*; D002140:California; D015984:Causality; D015897:Comorbidity; D042241:Early Diagnosis; D004562:Electrocardiography / Q000706:statistics & numerical data*; D005260:Female; D006323:Heart Arrest / Q000175:diagnosis / Q000401:mortality* / Q000517:prevention & control; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D015996:Survival Rate; D017216:Telemedicine; D013686:Telemetry / Q000706:statistics & numerical data*
keywords: Arrhythmias; Cardiopulmonary arrest; Critical care; ECG; Physiologic monitoring; Telemetry