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............................................................................................................................................................................. When a diagnosis is nearly certain or highly likely, no further evaluation is needed, and treatment—if any—can be planned. In other cases, the initial evaluation may suggest a diagnosis when the features listed in Table 5 are present, or otherwise is unable to suggest any diagnosis. 4.1.2 Management of syncope in the emergency department based on risk stratification The management of TLOC of suspected syncopal nature in the ED should answer the following three key questions:

(1) Is there a serious underlying cause that can be identified? (2) What is the risk of a serious outcome? (3) Should the patient be admitted to hospital?

Figure 5 shows a flow chart for the management and risk stratification of patients referred to the ED for TLOC suspected to be syncope (modified from Casagranda et al.40).

Question 1: Is there a serious underlying cause that can be identified in the ED? Normally the presenting complaint of syncope can be established. The primary aim for an ED clinician is then to establish an underlying diagnosis, especially those associated with the potential for rapid clinical deterioration.41,42 It is the acute underlying disease that most frequently determines short-term adverse events rather than the syncope itself.43 Subsequent management will focus on treating this underlying cause (Figure 5). Many (40–45%) non-cardiovascular and some cardiovascular life-threatening underlying conditions are obvious in the ED.44 Table 6 lists high-risk features that suggest the presence of a serious underlying cause and low-risk features that suggest a benign underlying cause.

Question 2: What is the risk of a serious outcome? High-risk features are shown in Table 6, and how to use this risk profile to guide subsequent management and disposition is shown in Figure 6.

Risk stratification is important, for two reasons:

(1) To recognize patients with a likely low-risk condition able to be discharged with adequate patient education. (2) To recognize patients with a likely high-risk cardiovascular condition requiring urgent investigation. This may require admission.

High-risk patients are more likely to have cardiac syncope. Structural heart disease25–27,31,35,36,45 and primary electrical disease46 are major risk factors for sudden cardiac death (SCD) and overall mortality in patients with syncope. Low-risk patients are more likely to have reflex syncope and have an excellent prognosis.47 OH is associated with a two-fold higher risk of death owing to the severity of comorbidities compared with the general population.48

Question 3: Should the patient be admitted to hospital? Approximately 50% of patients who present to the ED with syncope are admitted (although the rate varies between 12–86%) (see Supplementary Data Table 4). The use of clinical decision rules and standardized protocols has not changed this rate significantly. The composite estimate of outcomes is that in the next 7–30 days, only 0.8% die and 6.9% have a non-fatal severe outcome whilst in the ED, while another 3.6% have a post-ED serious outcome (see Supplementary Data Table 4). Unnecessary admission in low-risk patients can be harmful.87 Whereas it is crucial to identify these high-risk patients to ensure early, rapid, and intensive investigation, not all patients at high risk need hospitalization.80

Table 5 Clinical features that can suggest a diagnosis on initial evaluation

Reflex syncope • Long history of recurrent syncope, in particular occurring before the age of 40 years • After unpleasant sight, sound, smell, or pain • Prolonged standing • During meal • Being in crowded and/or hot places • Autonomic activation before syncope: pallor, sweating, and/

or nausea/vomiting • With head rotation or pressure on carotid sinus (as in tu-

mours, shaving, tight collars) • Absence of heart disease

Syncope due to OH • While or after standing • Prolonged standing • Standing after exertion • Post-prandial hypotension • Temporal relationship with start or changes of dosage of vas-

odepressive drugs or diuretics leading to hypotension • Presence of autonomic neuropathy or parkinsonism

Cardiac syncope • During exertion or when supine • Sudden onset palpitation immediately followed by syncope • Family history of unexplained sudden death at young age • Presence of structural heart disease or coronary artery

disease • ECG findings suggesting arrhythmic syncope: - Bifascicular block (defined as either left or right BBB com-

bined with left anterior or left posterior fascicular block) - Other intraventricular conduction abnormalities (QRS duration >_0.12 s) - Mobitz I second-degree AV block and 1 degree AV block with markedly prolonged PR interval - Asymptomatic mild inappropriate sinus bradycardia (40–50 b.p.m.) or slow atrial fibrillation (40–50 b.p.m.) in the absence of negatively chronotropic medications - Non-sustained VT - Pre-excited QRS complexes - Long or short QT intervals - Early repolarization - ST-segment elevation with type 1 morphology in leads V1-V3 (Brugada pattern) - Negative T waves in right precordial leads, epsilon waves suggestive of ARVC - Left ventricular hypertrophy suggesting hypertrophic cardiomyopathy

ARVC = arrhythmogenic right ventricular cardiomyopathy; AV = atrioventricular; BBB = bundle branch block; b.p.m. = beats per minute; ECG = electrocardiogram; OH = orthostatic hypotension; VT = ventricular tachycardia. Downloaded from academic.oup.com/eurheartj/article/39/21/1883/4939241 by guest on 07 October 2026