Syncope — viva

Stem

Practice viva. You are the cardiology registrar asked to see a 35-year-old woman in the emergency department who fainted while standing in a queue in a hot, crowded pharmacy after a few minutes of progressively feeling hot, sweaty and nauseated. The examiner works through definitions, the initial evaluation, risk, tests, treatment and driving.^[1]

Branch A — Was it syncope?

Examiner: How do you define syncope, and what else causes transient loss of consciousness?

Strong answer:

• European Society of Cardiology (ESC) 2018 defines syncope as transient loss of consciousness (TLOC) due to cerebral hypoperfusion, characterised by a rapid onset, short duration and spontaneous complete recovery.^[1]
• ESC 2018 groups non-traumatic TLOC into syncope, epileptic seizures, psychogenic TLOC and a miscellaneous group of rare causes, in that order of occurrence.^[1]
• ESC 2018 lists four features of TLOC: short duration, abnormal motor control, loss of responsiveness, and amnesia for the period of loss of consciousness.^[1]

Examiner: What would make you think of a mimic?

• ESC 2018 Table 4: in psychogenic pseudosyncope, apparent loss of consciousness lasts many minutes to hours, at high frequency, up to several times a day.^[1]
• ESC 2018 Table 4: in a vertebrobasilar transient ischaemic attack (TIA) there are always focal neurological signs and symptoms, usually without loss of consciousness.^[1]
• ESC 2018 Table 4: in cardiac arrest there is loss of consciousness yet no spontaneous recovery.^[1]

Branch B — The initial evaluation

Examiner: What is your initial evaluation, and when is it diagnostic?

• ESC 2018: careful history with eyewitness accounts, physical examination including supine and standing blood pressure (BP), and an electrocardiogram (ECG).^[1]
• American College of Cardiology/American Heart Association/Heart Rhythm Society (ACC/AHA/HRS) 2017 recommends a detailed history and physical examination (class of recommendation [COR] I, level of evidence [LOE] B-NR) and calls a resting 12-lead ECG useful in the initial evaluation (COR I, LOE B-NR).^[2]
• ESC 2018 calls vasovagal syncope (VVS) highly probable if syncope is precipitated by pain, fear or standing and is associated with a typical progressive prodrome of pallor, sweating and/or nausea (Class I, Level C).^[1]
• ESC 2018 states that when a diagnosis is nearly certain or highly likely, no further evaluation is needed and treatment, if any, can be planned.^[1]

Branch C — Risk and disposition

Examiner: Her examination and ECG are normal. Can she go home?

• ESC 2018 Table 6 lists a prodrome typical of reflex syncope, syncope after prolonged standing or in crowded, hot places, a normal examination and a normal ECG as low-risk features.^[1]
• ESC 2018 recommends that patients with low-risk features, likely to have reflex or situational syncope or syncope due to orthostatic hypotension (OH), are discharged from the emergency department (ED) (Class I, Level B).^[1]
• ACC/AHA/HRS 2017 states that it is reasonable to manage presumptive reflex-mediated syncope in the outpatient setting in the absence of serious medical conditions (COR IIa, LOE C-LD).^[2]

Examiner: Which features would have changed that?

• ESC 2018 Table 6 major features of the event: new onset of chest discomfort, breathlessness, abdominal pain or headache; syncope during exertion or when supine; sudden onset palpitation immediately followed by syncope.^[1]
• ESC 2018 Table 6 major examination features: unexplained systolic BP in the ED below 90 mmHg, suggestion of gastrointestinal bleed on rectal examination, persistent bradycardia below 40 beats per minute (b.p.m.) in the awake state without physical training, and an undiagnosed systolic murmur.^[1]

Branch D — Tests

Examiner: Would you order a tilt test or a brain scan?

• Her VVS is already highly probable on ESC 2018 criteria, and ESC 2018 says that when a diagnosis is nearly certain or highly likely, no further evaluation is needed, so she does not need a diagnostic tilt test; the tilt rows below are for a diagnosis that is suspected but not confirmed.^[1][4][2]
• ESC 2018 grades tilt testing Class IIa, Level B in suspected reflex syncope, orthostatic hypotension (OH), postural orthostatic tachycardia syndrome (POTS) or psychogenic pseudosyncope; for suspected recurrent reflex syncope the newer ESC 2021 row applies among the ESC guidelines checked for this topic, and for other suspected reflex syncope (such as a first faint) and for OH, POTS and psychogenic pseudosyncope none of the newer ESC guidelines checked for this topic has a tilt-testing row, so the 2018 row is given as current.^[1][4]
• ACC/AHA/HRS 2017: tilt-table testing can be useful for suspected VVS if the diagnosis is unclear after initial evaluation (COR IIa, LOE B-R); her VVS is already highly probable on ESC 2018 criteria (standing trigger with a progressive prodrome of sweating and nausea).^[2][1]
• ESC 2018 adds that a negative tilt response does not exclude reflex syncope, and that tilt testing should not be used to assess drug efficacy.^[1]
• ESC 2018 states that electroencephalography (EEG), neck artery ultrasound and brain computed tomography (CT) or magnetic resonance imaging (MRI) are not indicated in patients with syncope (Class III, Level B).^[1]

Examiner: She returns a year later with faints every few months. How would you monitor her?

• First establish how frequent and how severe the faints are: ESC 2018 says an implantable loop recorder (ILR) should be considered in suspected or certain reflex syncope presenting with frequent or severe syncopal episodes (Class IIa, Level B), so that row applies to her only if her faints are frequent or severe.^[1]
• The ESC 2018 Class I, Level A early-phase ILR row applies only if the origin is uncertain: recurrent syncope of uncertain origin, without high-risk criteria and with a high likelihood of recurrence within the device battery life.^[1]
• ACC/AHA/HRS 2017 states that the choice of a specific cardiac monitor should be determined by the frequency and nature of syncope events (COR I, LOE C-EO).^[2]

Branch E — Treatment

Examiner: How do you treat recurrent vasovagal syncope?

• ESC 2018: explanation of the diagnosis, reassurance, explanation of the risk of recurrence and avoidance of triggers and situations in all patients (Class I, Level B); ACC/AHA/HRS 2017: patient education on the diagnosis and prognosis of VVS (COR I, LOE C-EO).^[1][2]
• ESC 2018: isometric counter-pressure manoeuvres should be considered in patients with prodromes who are under 60 years (Class IIa, Level B).^[1]
• ESC 2018: beta-adrenergic blocking drugs are not indicated (Class III, Level A); ACC/AHA/HRS 2017: beta blockers might be reasonable in patients 42 years of age or older with recurrent VVS (COR IIb, LOE B-NR).^[1][2]
• ACC/AHA/HRS 2017: midodrine is reasonable in recurrent VVS with no history of hypertension, heart failure or urinary retention (COR IIa, LOE B-R).^[2]

Branch F — Driving

Examiner: She asks about driving her car.

• ACC/AHA/HRS 2017 states that it can be beneficial for clinicians to know the driving laws and restrictions in their regions and discuss the implications with the patient (COR IIa, LOE C-EO).^[2]
• ACC/AHA/HRS 2017 Table 10 suggests no restriction for VVS with no syncope in the prior year, 1 month for 1–6 syncope per year, and not fit to drive until symptoms resolve for more than 6 per year.^[2]
• Her severity decides the ESC advice: if her reflex syncope falls in the ESC 2018 Web Table 3 "single/mild" group, ESC 2018 Web Table 3 advises no restrictions for group 1 (private) drivers unless it occurred during driving.^[3]
• If it falls in the "recurrent and severe" group, ESC 2018 Web Table 3 advises group 1 (private) drivers to wait until successful treatment is established.^[3]