Syncope accounts for a significant proportion of Emergency Department presentations and hospital admissions.

Despite this, many patients undergo extensive investigations with relatively low diagnostic yield, while others with life-threatening cardiac causes are missed.

This paper synthesises the current evidence and integrates recommendations from the European Society of Cardiology (ESC) and American ACC/AHA/HRS syncope guidelines into a practical approach for clinicians.

THE PAPER
Rose Anne Kenny. Syncope. N Engl J Med 2026;395:582–591

The major message from this review is:

The diagnosis of syncope is usually made from the history, examination, orthostatic blood pressure and ECG—not from indiscriminate testing.

Risk stratification should then determine who requires further investigation or admission.

A further major point is that older patients often present with unexplained falls rather than obvious syncope, and many of these falls may actually represent unwitnessed syncope.

Definition

Syncope is:

• transient loss of consciousness, due to transient cerebral hypoperfusion

• associated with loss of postural tone

• followed by rapid spontaneous recovery to baseline.

Episodes usually last less than one minute.

The review divides syncope into three major mechanisms:

• Reflex syncope: (90% of cases in younger adults and 40% among older adults)

• • vasovagal syncope: It is a reflex that results from bradycardia (vagal excess), hypotension (withdrawal of sympathetic innervation), or most commonly, a combination of the two. Usually associated with a systolic blood pressure of no more than 80 mm Hg, a heart rate of less than 40 beats per minute, or asystole lasting at least 3 seconds.

  • situational syncope: is due to an action or situation such as emotional stress, micturition, swallowing, or coughing.

  • carotid sinus syndrome: It is associated with carotid sinus hypersensitivity and occurs during carotid sinus massage. It results in a pause lasting at least 3 seconds or by a decrease in the systolic blood pressure of at least 50 mm Hg. It occurs almost exclusively in older adults and accounts for 9 to 17% of syncopal events and up to 30% of unexplained falls. 

  • Features of Reflex Syncope

    • Long history of recurrent syncope, in particular occurring before the age of 40 yr

    • after unpleasant sight, sound, smell, or pain 

    • Occurrence with prolonged standing

    • Occurrence during meal

    • Occurrence in crowded or hot places

    • Autonomic activation before syncope: pallor, sweating, nausea, or vomiting

    • Occurrence with head rotation or pressure on carotid sinus (e.g., due to tumors, shaving, or tight collars)

    • Absence of heart disease

• Orthostatic hypotension

  • Prevalence increases with age and is defined as a decrease of > 20 mmHg in systolic blood pressure or > 10 mmHg in diastolic blood pressure within 3 minutes of standing. It may occur initially  within 15 seconds of standing or be delayed and occur following prolonged standing. Neurogenic orthostatic hypotension results from autonomic nervous system dysfunction due to central or peripheral neurologic disease.

  • Affects less than 5% younger than 50 years of age, more than 20% of of those older than 70 years of age, and up to 68% of older adults living in institutional settings.

  • Features of orthostatic hypotension:

    • Occurs shortly after standing or with prolonged standing or with standing after exertion

    • Postprandial hypotension is defined as a > 20 mm Hg decrease in the systolic blood pressure of at within 2 hours of a meal . It is due to impaired cardiovascular compensation for splanchnic blood pooling during digestion

    • Following initiation or changes to dose of vasodepressive drugs or diuretics resulting in hypotension

    • Presence of autonomic neuropathy or parkinsonism

        

• Cardiac syncope

  • It results from conditions such as arrhythmias, structural heart disease, pulmonary hypertension and vascular disorders such as pulmonary embolism and aortic dissection, that may cause reduced cardiac output or cerebral perfusion. It occurs in up to 5% in younger adults, reaching 30% in older patients and leading to higher morbidity and mortality
  • Features

    • Occurrs during exertion or when supine

    • Palpitations followed by syncope

    • Family history of unexplained sudden death at young age

    • Pulmonary hypertension or structural heart, coronary artery, or pericardial disease

    • ECG findings suggesting arrhythmia causing syncope:

      • Bifascicular block 

      • Intraventricular conduction abnormalities (QRS duration, ≥0.12 sec)

      • Mobitz type I second-degree atrioventricular block and first-degree atrioventricular block with markedly prolonged PR interval

      • Asymptomatic mild sinus bradycardia (40–50 beats/min)or slow atrial fibrillation (40–50 beats/min) not caused by negatively chronotropic medications

      • Nonsustained ventricular tachycardia

      • Pre-excited QRS complexes

      • Long / short QT intervals

      • Early repolarization

      • Brugada Syndrome with ST-segment elevation with type 1 morphology in V1, V2, and V3

      • Negative T waves in right precordial leads and epsilon waves suggestive of arrhythmogenic right ventricular cardiomyopathy

      • Left ventricular hypertrophy suggesting hypertrophic cardiomyopathy

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• A particularly important point is that older patients often present with unexplained falls rather than obvious syncope, and many of these falls may actually represent unwitnessed syncope.

Syncope mimics

The most common is epilepsy. Urinary incontinence does not distinguish between syncope and epilepsy and may occur in 10 to 20% of syncopal events.  Other features often attributed to epilepsy such as tongue biting, jerking movements, and post event drowsiness also occur in syncope.

 The review examines:

• causes of syncope

• evidence supporting diagnostic strategies

• risk stratification

• investigations

• management

• disposition from ED

• management of older adults

• comparison of contemporary international guidelines.

What they found

Start with History, Physical Exam, Orthostatic BP and ECG

A careful history includes the events of the current episode and any previous episodes, as well as eyewitness accounts. It should include:

• triggers

• posture and activity: prolonged standing, hot environments

• prodrome if any, as well as what happenned during and after the event: emotional stress, pain, sweating, nausea, meals.

• any cardiac or neurological history

• the following finding may not be helpful as they occur in seizures as well as syncope:

  • urinary incontinence occurs in 10–20% of syncope, 

  • tongue biting can occur in both

  • brief post-event confusion can occur in syncope.

• medication review.

Actively look for:

• medication-induced hypotension

• neurogenic orthostatic hypotension

• postprandial hypotension

• dehydration.

This is particularly important in older patients.

Features that increase the probability of cardiac syncope include:

• age > 60

• Known heart disease: structural heart disease, valvular heart disease, congenital heart disease

• exertional syncope

• syncope while seated or supine

• sudden collapse without warning

• chest pain

• palpitations

• abnormal ECG

• family history of sudden cardiac death.

These patients require urgent investigation.

Target Investigations 

Routine CT brain scans, EEGs and large blood panels are discouraged.

Investigations depend on suspected mechanism. Here is a recommended approach:

Who needs admission?

One of the strongest practical messages concerns ED disposition.

Low-risk patients

Can usually be discharged.

Intermediate-risk patients

May benefit from an Emergency Department Observation Unit with approximately 6–12 hours of monitoring.

High-risk patients

Require hospital admission.

The review cites randomised evidence demonstrating that ED observation produces similar clinical outcomes to admission but at substantially lower cost.

Management

Treatment should target the mechanism, not simply the diagnosis.

Reflex / Orthostatic syncope

Management includes:

• hydration

• increased salt intake where appropriate

• avoidance of triggers

• medication review: note that the lowest risk of hypotensive events were associated with angiotensin-converting–enzyme inhibitors (odds ratio, 0.85; 95% CI, 0.81 to 0.89) and calcium-channel blockers (odds ratio, 0.81; 95% CI, 0.74 to 0.90).42

• reduction of culprit antihypertensives

• reduction of psychotropic medications.

For persistent orthostatic hypotension Midodrine and Droxidopa have been found to consistently reduce orthostatic symptoms. Evidence for fludrocortisone remains modest.

Bradycardic syncope

Patients with documented symptomatic bradycardia benefit substantially from pacing.

Meta-analysis demonstrated greater than 50% reduction in recurrent syncope following pacemaker implantation in appropriately selected patients.

Complex Syncope

This occurs where multiple mechanisms coexist. This most often occurs in older patients. For example, the following can occur simultaneously:

• carotid sinus syndrome

• orthostatic hypotension

• medication-related hypotension

• conduction disease

Guidelines

The review compares:

• ESC 2018 Guidelines

• ACC/AHA/HRS Guidelines

Both recommend:

• history

• examination

• ECG

• orthostatic blood pressure

• risk stratification.

However, the ESC guidelines place greater emphasis on:

• dedicated syncope clinics

• earlier implantable loop recorder use

• behavioural interventions for reflex syncope.

What does this mean in practice?

✅ 1. Trust your history

Most diagnoses can be made without extensive testing.

✅ 2. Perform orthostatic blood pressures routinely

They remain one of the highest-yield bedside investigations.

✅ 3. Risk-stratify, don't admit everyone

Observation units are underused and supported by evidence.

✅ 4. Think cardiac until proven otherwise in older patients

Particularly with:

• exertional syncope

• minimal prodrome

• abnormal ECG

• structural heart disease.

✅ 5. Don't diagnose seizure because of urinary incontinence

This review clearly dispels that common misconception.

✅ 6. Review medications carefully

Many episodes are medication-related and potentially preventable.

✅ 7. Think of syncope in every unexplained fall

Especially in patients over 65 years.

This may be the single biggest practice-changing message for Emergency Physicians.

Bottom Line

The message is simple:

History → Examination → Orthostatic BP → ECG → Risk Stratification → Targeted Investigation → Mechanism-Specific Treatment

Avoid indiscriminate testing, identify high-risk cardiac syncope early, recognise that unexplained falls in older adults often represent syncope, and use observation units for appropriately selected intermediate-risk patients. It is an excellent update.

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