Lecture Notes

Syncope is an extremely common presenting complaint to the Emergency Department. Thanks largely to a lack of externally validated and widely accepted clinical decision rule, enormous practice variation exists in working up and managing these patients.  Here, I will review an evidenced-based, three step approach to the ED work-up of syncope.

Step 1: Syncope versus Mechanical Fall or Seizure

It can be surprisingly difficult to differentiate among these three. A report of shaking could be myoclonic jerks from syncope or tonic-clonic jerks from a seizure. Seizure and syncope can both present with urinary or fecal incontinence. Lateral tongue biting or post-ictal confusion favors seizure over syncope. Remembering falling (without a podrome) favors mechanical fall over seizure. Oftentimes, patients present without witnesses or their own memory for what happened; they would then require work up for all three - seizure, syncope and mechanical fall.

Step 2: True Syncope versus Symptom Syncope

Syncope etiology includes dangerous arrhythmias, benign causes, or any potentially deadly disease process. The history and physical exam is to investigate for these other dangerous diseases. Chest pain plus syncope? Be concerned for a thoracic aortic dissection or acute coronary syndrome. Abdominal pain plus syncope? AAA or abdominal catastrophe. Black stool plus syncope? Upper GI Bleed. And so forth. On the other hand, true syncope is defined as: asymptomatic, +/- podrome, brief loss of consciousness with a return to an asymptomatic baseline. Combining true and symptom syncope patients in a clinical decision rule is impossible as it then must identify those at risk for a dangerous arrhythmia as well as any other dangerous disease resulting in syncope.

 Of note, every patient that presents to the ED with syncope should get an ECG. Labs, head CT, and chest X-ray are not indicated in the general syncope population. I personally obtain a CBC, BMP, and troponin (not evidence based!!!) on all syncope patients over 50 years old. An elevated troponin is associated with increased short term poor outcome and patients with positive troponins and syncope should be admitted. 

Step 3: Arrythmia Risk

For true syncope patients, the next step is to assess risk for an arrythmia. Numerous papers have attempted to clearly define which features confer an elevated risk, but, they frequently contradict each other. So, I combed the literature and came up with these 6 features that consistently confer an elevated risk of arrhythmia and thus, require admission. Here’s my mnemonic:  FA HE HE.

  • Family history (sudden cardiac death at young age or sudden death at a young age of unknown cause)

  • Age (Super tricky. The older the patient, the older the heart and the more prone that heart is to arrhythmia. Previous failed clinical decision rules use an age cutoff of 65 years old for high risk and I find this age cutoff used frequently.  Yet, the best evidence, and ACEP’s clinical policy, does not support any specific age cutoff .)

  • Heart (history of CHF, ACS, or structural heart disease)

  • Exertion (exertional syncope should be admitted)

  • Hypotension (measured in the field or in the ED)

  • ECG abnormal

  1. Nonsinus: Vtach/fib, Afib/flutter, 2nd and 3rd degree AV blocks, numerous PACs, PVCs.

  2. Intervals: prolonged QTc, wide QRS (LBBB/RBBB), LAFB/LPFB,

  3. Ischemia: ST elevations or depressions, q waves, T wave inversions

  4. Syndomes: WPW, HCOM, ARVD, brugada

Lastly, a new clinical decision rule the Canadian syncope rule is pending external validation. After analyzing outcomes in an adult syncope population in the ED without diagnosed cause at the end of their ED visit. Notice, they evaluated a population of patients with true syncope. They came up with a mix of features – history of heart disease, predisposition, hypotension/hypertension, elevated troponin, abnormal QRS axis, QRS> 130ms, QT > 480ms, diagnosis of vasovagal or cardiac syncope - that are each given a certain number of positive or negative points. The point totals correlated linearly with adverse outcome with scores of 0 or less being low risk (adverse outcome < 2%).  

And that’s 1-2-3 Syncope

Step 1: Syncope versus Mechanical Fall or Seizure
Step 2: True Syncope versus Symptom Syncope
Step 3: Arrythmia Risk (FAHEHE & Canadian)

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