Prospective Validation of a Clinical Decision Rule to Identify ED Chest Pain Patients Who Can Safely be Removed from Cardiac Monitoring

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1 Prospective Validation of a Clinical Decision Rule to Identify ED Chest Pain Patients Who Can Safely be Removed from Cardiac Monitoring Department of Emergency Medicine CAEP 2015 Shahbaz Syed PGY 3 FRCP Emergency Medicine

2 Shahbaz Syed MD Hina Chaudry MBBS Mathieu Gatien MD Soo Min Kim BScH Jeff Perry MD Kenneth Kwong BScH Muhammad Mukarram MBBS Venkatesh Thiruganasambandamoorthy MBBS Department of Emergency Medicine Ottawa Hospital Research Institute University of Ottawa, Ottawa, ON Funded by the Ontario Innovation Fund No Financial COI to Disclose

3 Cardiac Monitoring: The Clinical Problem Monitored beds are premium in the ED, especially during times of overcrowding Potentially sicker patients in the waiting room Is there a way to determine which chest pain patients may safely be removed from monitor?

4 Background Largest study of arrhythmia in admitted patients (Schull et al) 8932 patients; 20 patients (0.2%) had cardiac arrest ED study (Atzema et al) 0.2% of monitored alarm triggers resulted in a change in management Chest pain patients take up a significant proportion of cardiac monitors, but little to no research has been done on arrhythmia in these patients

5 Clinical Decision Rule Derivation 992 chest pain patients monitored in the ED 14% with MI, 12% with unstable angina 17 patients (1.7%) with serious arrhythmia detected in the ED Created decision rule had 100% sensitivity for serious arrhythmias Would allow physicians to remove 29% of patients from cardiac monitoring

6 Research Question Prospective validation of a decision rule to remove patients presenting to the ED with chest pain from cardiac monitoring Specific Objectives: 1) Evaluate performance of the decision rule 2) Determine safety 3) Determine clinical impact

7 The Rule 1. Patient is currently chest pain free 2. Patient has a normal or non specific ECG Classification based on internationally accepted standardized definition of ECG data coding

8 ECG Interpretation Cullen et al. 2010

9 ECG Interpretation Normal Non specific ST T wave changes Abnormal but not diagnostic of ischemia Bundle branch block, non sinus rhythm, interval prolongation, heart blocks LVH, Strain Ischemia/infarct known to be old Ischemia/infarct not known to be old Acute myocardial Infarction Uninterpretable Paced rhythm

10 Methods Design: Prospective validation study Setting: The Ottawa Hospital (>160,000 visits/year) Study Period: November 2013 April 2015 Physician enrollment (study forms) on all chest pain patients

11 Methods Inclusion Criteria: Patients presenting to the ED with chest pain On cardiac monitor Exclusion Criteria: Cardiac arrest prior to arrival STEMI on ECG ECG analysis conducted by physician blinded to outcomes

12 Methods Primary Outcome: Any new arrhythmia in the ED requiring treatment within 8 hours of presentation. All patients had an extensive chart review and 30 day phone call followup.

13 Baseline Characteristics Analysis of 1125 patients, 796 met inclusion criteria: Mean Age 63.8 Female 44.2% Coronary Artery Disease 36% Congestive Heart Failure 6% Hypertension 52% Diabetes 20% Pacemaker 4% Atrial Fibrillation 13% NSTEMI 2.4% Admitted Patients 8.9%

14 Rule Components Abnormal ECG Normal or non specific ECG Arrhythmia No arrhythmia Total Total Arrhythmia No arrhythmia Total On going chest pain Chest pain resolved Total

15 Results Arrhythmia No Arrhythmia Total Rule positive Rule negative Total Sensitivity: 100% ( % 95% CI) Specificity: 36.4% ( % 95% CI) PPV: 2.9% ( , 95% CI) NPV: 100% ( , 95% CI)

16 Pooled Data Analyzed pooled data using the initial derivation cohort: 1789 patients Combined outcome rate in both studies: 1.8%

17 Pooled Data Arrhythmia No Arrhythmia Total Rule positive Rule negative Total Sensitivity: 100% ( ) Specificity: 32.3% ( ) PPV: 2.62% ( ) NPV: 100% ( )

18 Discussion First study to prospectively evaluate monitoring of chest pain patients in the ED Arrhythmia is an uncommon problem among patients with chest pain 1.9% among monitored patients 1.3% among entire cohort In Our Cohort: 36% of patients were identified as low risk, and could have potentially been taken off cardiac monitor

19 Conclusions Successful prospective validation of decision rule to remove chest pain patients from cardiac monitor Arrhythmia in chest pain patients is uncommon; it appears that only patients with on going chest pain, and an abnormal ECG require cardiac monitoring In the combined derivation and validation cohorts 32% of patients were identified as low risk, and could have potentially been taken off cardiac monitor

20 Further Work Kappa analysis pending on ECG interpretation (dual physician to determine interrater reliability) Ultimately, may benefit from larger number of patients enrolled to increase outcome rate Prospective study examining implementation of decision rule

21 The Rule 1. Patient is currently chest pain free 2. Patient has a normal or non specific ECG

22 Acknowledgements Research Team: Dr. Mathieu Gatien Dr. Jeff Perry Dr. Venkatesh Thiruganasamandamoorthy Hina Chaudry Soo Min Kim Kenneth Kwong Muhammad Mukarram

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