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Key messages for GPs
- Syncope = transient loss of consciousness from cerebral hypoperfusion, rapid onset, short duration, spontaneous complete recovery. Long recovery → rethink the label.
- Patients say “blacked out / fainted / lights went out” — only a careful history puts them in the right bucket.
- Roughly 80% of collapses are reflex or orthostatic; the high-stakes minority is cardiac syncope (arrhythmia / structural disease).
- Red flags: exertional (during, not after), supine, injury from sudden fall, abnormal ECG, family SCD, known structural disease.
- Match monitoring to frequency; for rare recurrent events an implanted cardiac monitor (ICM) (~5-year battery) often beats a low-yield Holter.
- Driving rules hinge on the bucket: vasovagal often ~24 h; unexplained recurrent much longer; paced cardiac pauses can reopen driving quickly once treated.
What syncope is (and is not)
The speaker opened with the formal definition: transient loss of consciousness due to cerebral hypoperfusion — rapid onset, short duration, spontaneous complete recovery. Every clause matters. Prolonged unconsciousness is not syncope. A long, confused recovery is not typical syncope (think seizure, stroke mimic, intoxication). The brain briefly runs out of perfusion energy; the lights go out; they come back on when flow returns.
Lay language is messy. Map the patient’s words to mechanisms with history first — not with a premature category label.
Case: Gary and the implanted monitor
Gary, 50, had ~20 years of brief, sudden collapses without warning and with rapid recovery. Occasional racing heart. Worked up as epilepsy, started on valproate, lost his licence, kept collapsing every ~6 months. A new neurologist recognised a syncope story that did not fit a seizure box and referred to EP.
An implanted cardiac monitor (subcutaneous, multi-year battery) caught:
- AF with rapid ventricular rate (~6 h) — explained palpitations, not the syncope.
- Short SVT at ~180 bpm (~6 s) — asymptomatic, not the syncope.
- Then the kitchen collapse: sinus ~100 → abrupt pause (~8 s) → ventricular ectopic → sinus recovery — proven cardiac syncope.
Pacemaker → no further pauses/syncope. EP study found a left atrial bypass tract triggering SVT/AF; ablation cured both. Epilepsy label reversed, valproate stopped, driving restored after two decades. The lesson: confirm rhythm at the symptom moment; technology can reverse a wrong chronic label.
Three buckets
| Bucket | Typical clues | Risk / notes |
|---|---|---|
| Reflex (vasovagal / situational) | Prodrome; triggers (standing, heat, pain, blood, vaccines, smells); often younger | Usually benign; driving often short restriction once clear |
| Orthostatic | Upright BP fall; elderly; antihypertensives; dehydration; Parkinson’s / autonomic neuropathy | Danger often from falls/injury, not arrhythmia |
| Cardiac | Abrupt; little/no prodrome; abnormal ECG; structural disease; during exertion; supine | Higher mortality hazard — the bucket EP can often fix |
Red flags & bradycardia sorting
ECG screen in the rooms: awake sinus rate <40, pauses, AV conduction disease, long QT, pre-excitation. These are high-yield referral triggers.
Bradycardia context matters. Athlete resting rates ~30 can be physiologic. Elderly breathless bradycardia may need pacing. Sleep pauses and nocturnal Mobitz I are often benign; daytime Mobitz II / complete heart block are pathological pacing territory.
What you can do in the rooms
- 12-lead ECG
- Lying and standing blood pressures
- Medication review (especially BP drugs)
- Basic bloods
- Echo — low yield for pure syncope unless murmur / suspected structure; still a useful rule-out
- Monitoring matched to frequency: Holter if very frequent (yield often low); patch if weekly–monthly; ICM for rarer recurrent events (speaker: QCG often moves to ICM rather than long patches)
Driving (as presented — always check current Austroads / state advice): unexplained → often months off; vasovagal once clear → commonly ~24 h; untreated cardiac pauses → do not drive; after pacemaker for that indication → often back sooner (talk cited ~2 weeks); ICD rules differ for primary vs secondary prevention.
Pacing, CRT, leadless & remote monitoring
A rapid history of pacing: first implant 1958 (Arne Larsson story — outlived the inventor after many generators); mercury-zinc → brief nuclear experiments → lithium iodide; single → dual chamber; activity sensors; ICD born from Mirowski’s obsession after a mentor’s sudden death (initially mocked, then trial-proven); CRT (biventricular) for heart-failure synchrony; conduction-system pacing (His → now largely left bundle area pacing) to reduce pacing-induced cardiomyopathy; leadless ventricular pacemakers (Medtronic Micra family; Abbott dual-chamber leadless evolving — atrial components may still have access/prosthesis-list limits).
QCG remote monitoring (~4500 device patients cited): nightly transmissions, nurse + industry support, GP letters (often yearly compliance downloads), alerts for lead issues / new AF needing anticoagulation. Implant-site concerns (possible infection) warrant urgent contact — early antibiotics can sometimes avoid extraction.
When to refer
- Syncope with any red flag
- Symptomatic bradycardia, Mobitz II, or complete heart block → pacing pathway
- Unexplained recurrent syncope → consider ICM
- Existing cardiac device + new symptoms or implant-site change (infection risk)