New in EM 010: Can we predict poor outcomes with syncope?

29 May

Originally Published on RCEM Learning Podcast October 2017

As part of the RCEM Learning Podcast I record reviews of recent literature with Dave McCreary. We’ve been doing this for about a year now and you can hear them all on the RCEM Learning Podcast each month. I’d like to have them here and searchable on this site too so I’ll be posting the ones I find most relevant here. You can hear the newest ones by subscribing to the free RCEM Learning Podcast. 

Audio:


TitlePredicting Short-Term Risk of Arrhythmia among Patients with Syncope: The Canadian Syncope Arrhythmia Risk Score

Author: Vankatesh Thiruganasambandamoorthy. Academic Emergency Medicine. August 2017.

Background

Syncope accounts for 1-3% of ED visits (really? I’ve definitely had days where it feels like closer to 30%) and up to 3% of hospital admissions from the ED. It’s common, and on the surface it’s a pretty straightforward assessment process. But there are pitfalls and serious underlying conditions that we are considering during that process. The Canadian’s love a good prediction tool, and they’re recently turned their sights on syncope and trying to give us an objective tool to identify patients at risk of nastiness at 30 days from discharge. This paper is a furthering of that work to refine the tool to identify patients at risk of death or arrhythmia requiring intervention at 30-days – so those who would benefit from ECG monitoring.

Methods

  • Prospective, multi-centre cohort study
  • Population: Patients 16 years with syncope presenting within 24 hours of the event
  • Exclusion: Prolonged LOC >5 minutes, change from baseline mental status, witnessed seizure, or LOC following head injury.
  • Trained ED staff identified patients for inclusion and a raft of data variables was collected both at the time and through chart review. ECGs were all assessed by a cardiologist and abnormalities reviewed by a second cardiologist.
  • Primary outcome: Composite of death (due to arrhythmia or unknown cause), arrhythmia, or procedural interventions to treat arrhythmia within 30 days.
  • Apply fancy statistical analysis, allow to simmer, and serve up a tasty decision tool.

Results

  • 5,010 patients analysed
  • 106 patients (2.1%; 95% CI 1.7-2.5) met primary outcome
    • 45 (0.9%) of these occurred outside the hospital
    • 22 (0.45) patients died (15 from unknown cause), 13 of these were outside of the hospital
  • Final 8 independent predictors:
    • Vasovagal predisposition (warm crowded place, prolonged standing, fear, emotion, pain)
      • -1 point
    • History of heart disease (coronary, valvular, myopathy, CCF, non-sinus rhythm)
      • +1 point
    • Any SBP <90 or >180 mmHg in the ED
      • +1 point
    • ED Dx of vasovagal syncope or cardiogenic syncope
      • -1 point for vasovagal
      • +2 points for cardiogenic
    • Elevated trop (>99%ile)
      • +1 point
    • QRS Duration >130ms
      • +2 points
    • QTc >480ms
      • +1 point
    • Scoring 0 had sensitivity of 97.1% and specificity 53.45 for primary outcome

Bottom Line

Bad outcomes from syncope evaluated in the ED are rare but do happen. Like all of these decision aids, this is just putting an objective number to what most of us already do with clinical gestalt. But this sort of score would be easy to use to provide an objective risk assessment and aid decisions re admission or discharge, and on whom to arrange outpatient ambulatory ECG measurement.

Links

The San Francisco Syncope Rule has 96% sensitivity and 62% specificity for “death, myocardial infarction, arrhythmia, PE, stroke, SAH, significant haemorrhage, or any other condition causing a return to ED and hospitalisation for related event”.

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