EEM Rewind: Syncope ADP

Syncope is a common ED complaint with wide practice variation, low diagnostic yield from routine testing, and high disposition uncertainty. The Canadian Syncope Risk Score helps risk-stratify 30-day serious outcomes after a normal initial evaluation, while ECG red flags like abnormal axis, conduction delay, and prolonged QT can identify patients who should not be treated as benign.

Canadian Syncope Risk Pathway

• Risk score scope: The Canadian Syncope Risk Score applies to patients age 16 and older presenting within 24 hours of syncope after a thorough history, exam, and normal initial evaluation that has already ruled out obvious dangerous mimics.
• Thirty-day adverse events: The score predicts both arrhythmic outcomes such as pacemaker placement or death and non-arrhythmic events such as myocardial infarction or pulmonary embolism, which keeps the tool clinically grounded.
• Low-risk discharge signal: Low-risk patients were discharged home in this pathway, and only 0.2% later needed a significant intervention with no unexplained deaths, a reassuring benchmark for community ED practice.
• Medium-risk home monitoring: Medium-risk patients were discharged with real-time outpatient monitoring rather than routine admission, and 11% ultimately had a significant diagnosis requiring intervention. We get into how that discharge pathway works in the episode.
• High-risk admission default: High-risk patients were admitted rather than observed in an accelerated discharge pathway, underscoring that the score is meant to standardize disposition rather than replace judgment.

ECG and Initial Syncope Evaluation

• ECG danger findings: Post-syncope ECG review should actively look for abnormal axis, conduction delay, and prolonged QT because these are the patterns most likely to point toward a serious cardiac cause.
• Named ECG cutoffs: Useful red flags include axis at or below -30 or above 100 degrees, QRS over 130 ms, and QTc over 480 ms, specific thresholds worth keeping in mind at the bedside.
• Near-syncope equivalence: For this pathway, near syncope is treated like true syncope, a practical move that avoids under-triaging patients whose physiology may be identical despite less dramatic wording.
• Testing by suspicion: Additional testing should be driven by clinical suspicion rather than reflex panels, and troponin is not mandatory unless the presentation gives you a reason to look for myocardial injury.
• ED monitoring nuance: Monitor patients while initial results are pending, but do not prolong the ED stay just to accumulate telemetry time; for more complex cases, a short observation window may still be reasonable. We cover that bedside nuance on the show.

Real-Time Outpatient Monitoring

• Patch monitor model: The pathway uses a simple adhesive chest patch that provides continuous 24/7 telemetry with structured alarms and interventions, extending arrhythmia detection beyond the ED wall clock.
• Delayed event capture: The average clinically important event occurred around day 8 after placement, which explains why a brief ED monitor period can miss the very diagnoses that matter most.
• Fourteen-day duration: Monitors were typically applied for 14 days, matching the delayed timing of actionable events without defaulting medium-risk patients to hospital admission.
• Bradyarrhythmia predominance: In monitored medium-risk patients, bradyarrhythmias were found more often than tachyarrhythmias, and the most common downstream intervention was pacemaker placement.
• Operational feasibility: At roughly $300 per device placement, this approach pairs positive provider and patient feedback with a concrete operational cost that community hospitals can actually evaluate.

References:

1. Thiruganasambandamoorthy V, et al. Development of the Canadian Syncope Risk Score to predict serious adverse events after emergency department assessment of syncope. CMAJ. 2016;188(12):E289-E298. PMID: 27378464.
2. Thiruganasambandamoorthy V, et al. Multicenter Emergency Department Validation of the Canadian Syncope Risk Score. JAMA Intern Med. 2020;180(5):737-744. PMID: 32202605.