Rhythm triage for GPs: reassure, investigate, or same-day ED
QCG EP talk on incidental rhythms from wearables and Holters — green/amber/red thresholds, Mobitz I vs sick sinus, PVCs, non-sustained VT, flutter, new LBBB, and accessory pathways.
- Speaker
- Dr Thomas Walters — electrophysiologist (EP); returned from San Francisco after PhD; clinical interest in VT and PVCs. Host introduction frames him as “EP Thomas Walters” for this rhythm-management opener.
- Session host / colleagues mentioned
- QCG host introduces the EP block (AF talk by Mike; syncope talk; cases/Q&A). Dr John Hayes noted in the room; Sunshine Coast EP colleague mentioned (ASR garbled). Mike (QCG EP; host calls him the group “clown” / joker) is teed up for the AF ablation talk that follows.
- Session context
- Otter id
hplJBvnkENiKyRxT8BgwkPwPS7k· title Electrophysiology Rhythm Management · ~25.9 min (1554 s) · 2026-02-28. Companions: af-ablation-overview · cardiac-case-panel · cardiology-subspecialties.
Key messages for GPs
- Rhythm presentations are rising — partly true pathology, partly wearables sending asymptomatic people into clinic with screenshots.
- You need a simple toolbox: history → ECG → targeted tests → green / amber / red triage.
- History is the most important tool for palpitations and syncope — red flags beat any single wearable number.
- Night-time Wenckebach (Mobitz I) is usually physiology — reassure; compare with abrupt drop without PR lengthening (sick sinus territory).
- Narrow-complex ectopy and typical PVCs are often green/amber; high PVC burden (~15–20%+) can link to cardiomyopathy — echo + Holter matter.
- Atrial flutter is curable with ablation; anticoagulate by stroke risk like AF; if flecainide is used for AF, pair with an AV-nodal agent.
- Any clear accessory pathway → refer to EP (urgency from history). Worry about AF conducting over the pathway.
Wearables tsunami & triage colours
Walters opens with the clinic reality: limited time, limited resources, pressure to act. Consumer devices are not medical-grade — heart-rate accuracy can be off by ~15–20%. Always ask: what did they capture, what symptoms at the time, and does the ECG (or Holter) confirm it?
He colour-codes action for GPs:
About five–six electrophysiologists, remote-monitoring nurses, >4500 intracardiac devices under follow-up, and hundreds of AF procedures yearly. Device alerts (AF, lead issues, battery) are a team sport — not just the lab.
History toolbox
For palpitations, ask whether they sound like a re-entrant circuit: sudden flip on/off (e.g. sitting, then 180–200 bpm, then abruptly back) versus gradual rise and fall (more sinus / catecholamine-driven).
For syncope, rebuild the day: hydration, minute-by-minute for 5–10 minutes before, witness account, recovery (confused post-ictal vs quick recovery). Red flags include exertion, supine/unheralded events, chest pain, dyspnoea, prolonged prodrome less typical of simple vagal.
Past history that raises pre-test risk: family sudden arrhythmic death (especially <40, definitely <20), structural heart disease, prior ischaemic scar (substrate for re-entrant VT). Listen for AS / HOCM clues; check QTc; consider simple clinic stress (walk with pulse oximeter, lying/standing).
Incidental findings (green → red)
Asymptomatic wearable heart-rate ranges
A night-time “range” on a watch without symptoms is usually observation and education — context first, not panic referral. Confirm with proper ECG/Holter when the story or risk is unclear.
Mobitz I (Wenckebach) at night
Sinus with progressive PR lengthening then a dropped beat — classic increased vagal tone. Walters’ toilet-flush analogy: the AV node needs time to “refill”; at night it takes longer until one beat is skipped. Most of us do this asleep. Asterisk: consider OSA if vagal tone seems excessive.
Sick sinus / abrupt pauses
Contrast case: PR intervals stay flat, then abrupt drop with escape beats and light-headed symptoms — sick sinus territory. Urgency is heterogeneous and history-driven; the case needed pacemaker (and surgery clearance). Check TFTs, stop culprits (e.g. beta-blockers) when relevant.
Supraventricular ectopy vs PVCs
If QRS morphology stays the same as sinus → beats originate above the AV node (supraventricular) — often green, short-lived skip beats. Classic PVCs: broad QRS, compensatory pause; the “thump” is often the next sinus beat after a filled ventricle. Green/amber: reassure, educate, optional beta-blocker for symptoms; echo if concern; Holter for burden.
Burden ~15–20%+ can associate with cardiomyopathy. Echo + Holter; look at morphology (outflow-tract patterns often friendlier), QTc, Q waves/scar, multiple morphologies. Not usually same-day ED if stable — but EP will want to help high-burden or heart-failure phenotypes.
Non-sustained VT
Broad-complex tachycardia <30 s, especially asymptomatic on a wearable, is a modern conundrum. Work the pre-test probability: exertion, syncope, family history, known IHD. Beta-blockers, stress testing, and ablation are in the specialist toolkit. Pragmatic same-day referral from clinic is “absolutely fine.”
Atrial flutter
Sawtooth; often 2:1 → ventricular rate ~150. Curable with ablation. Assess heart failure, rate control, anticoagulation by stroke risk. Side note: flecainide can organise AF into flutter — guidelines expect an AV-nodal slowing drug alongside.
New left bundle branch block
New RBBB is often benign; new LBBB needs more interest. Sweaty/clammy presentation → think ACS (including silent ischaemia in diabetes). LBBB + RAD + long PR → trifascicular concern / pacing risk. Hypertension is a common chronic cause; echo is reasonable when history is milder (amber).
Accessory pathway (not “just PVCs”)
Teen case discharged as “PVCs” — GP recognised pre-excitation and referred well. Any accessory pathway → EP referral; urgency from syncope, sustained palpitations, echo for structure. Why AF matters: AV node is a protective “toilet flush”; an accessory pathway is “on tap” and can conduct AF into dangerous broad complex rates → VF risk.
What you can do in the rooms
- Wearable trick: lead I with hands on watch; place watch on ankle for a lead-II-like vector — two ECGs to bring out flutter waves / P waves.
- Pulse oximeter walk for chronotropic response; lying/standing BP for pre-syncope.
- Bloods: TFTs (and context-appropriate workup); echo early for structure.
- Match the test to the story: exertional → stress test / stress echo; vagal/postural → tilt pathway.
Clinic checklist
- Ask symptoms at the moment of the wearable alert — asymptomatic ranges rarely need urgent EP.
- Separate Mobitz I (lengthening PR) from abrupt sick-sinus drops.
- Same QRS morphology → supraventricular ectopy; broad different QRS → ventricular; quantify PVC burden.
- Flutter: anticoagulate appropriately; think ablation cure; don’t use flecainide without AV nodal cover.
- New LBBB / pre-excitation / syncope + broad complex → escalate; accessory pathway always to EP.
- Prefer a transthoracic echo before/with referral when structure might change urgency — speeds EP assessment.