What initial assessments should I perform for a patient presenting with syncope to rule out serious underlying conditions?

Initial assessments for a patient presenting with syncope to exclude serious underlying conditions include:

• Obtain a detailed history of the event from the patient and any witnesses, including circumstances before, during, and after the transient loss of consciousness (TLoC), posture immediately before, prodromal symptoms (e.g., sweating, feeling warm), appearance and colour during the event, presence or absence of movements such as limb-jerking, tongue-biting (noting side or tip), injury details, event duration, and recovery features such as confusion or weakness on one side.
• Use this information to confirm that TLoC occurred; if uncertain, assume TLoC until proven otherwise.
• Perform a physical examination including a full cardiovascular exam and measure lying and standing blood pressure to assess for postural hypotension.
• Assess for features suggestive of serious cardiac conditions such as heart failure signs, heart murmur, TLoC during exertion, family history of sudden cardiac death under 40 years or inherited cardiac conditions, and new or unexplained breathlessness.
• Record and interpret a 12-lead ECG promptly to identify arrhythmias or other cardiac abnormalities.
• Identify features suggestive of epileptic seizures (e.g., bitten tongue, head turning, prolonged limb jerking, confusion post-event) to differentiate from syncope.
• Consider referral for specialist cardiovascular assessment if any concerning features are present or if diagnosis is uncertain after initial assessment.

These steps help exclude serious underlying causes such as cardiac arrhythmias, structural heart disease, or epilepsy and guide appropriate management and referral.

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