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cardio.atrial_flutter.wpw-preexcited.v1PRODUCTION
cardio.atrial_flutter.wpw-preexcited.v1

Pre-excited atrial flutter (WPW) — DCCV / procainamide; AV-nodal blockers ABSOLUTELY contraindicated

cardiologyacuteadult
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11/12 authored

Canonical 12-phase frame with authored status for this dossier.

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Detailed

Pre-excited atrial flutter = flutter/AF conducting antegrade down a non-decremental accessory pathway → potentially very rapid broad tachycardia that can degenerate to VF. The single most important rule: NO AV-nodal blockers (adenosine, IV diltiazem/verapamil, beta-blockers, digoxin, IV amiodarone)

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pre-excited mechanism framed + AV-nodal-blocker contraindication flagged

Patient inputs (10)

Younger patients with WPW + pre-excited AF/flutter are at particular SCD risk; age frames ablation urgency and occupational/sports clearance

Haemodynamic stability determines immediate synchronised DCCV vs a controlled pharmacologic strategy

Very high ventricular rates and a short shortest-pre-excited R-R interval mark high VF risk

Prior documented pre-excitation greatly raises pretest probability and immediately invokes the AV-nodal-blocker contraindication

Defines the broad irregular pre-excited morphology, the shortest pre-excited RR (risk marker), and differentiates from VT/SVT-with-aberrancy

Potassium/magnesium correction supports rhythm stability and antiarrhythmic safety (QT for ibutilide)

Inadvertent adenosine/AV-nodal blocker administration can precipitate VF and changes immediate management/monitoring

Rate-related demand ischaemia or a degenerating arrhythmia may elevate troponin; informs disposition

Informs ablation planning and pregnancy considerations for antiarrhythmic selection

Procainamide/ibutilide selection and ablation planning depend on structural heart disease and LV function

* = hard-required. Engine cannot meaningfully run until these are filled.

Severity triggers (5)

5 need judgement
  • informationalseverehaemodynamic_instability_with_pre_excited_tachyarrhythmia
    Pre-excited atrial flutter/AF with hypotension, shock, ischaemia, pulmonary oedema or depressed consciousness — immediate synchronised DC cardioversion is mandatory; no time for pharmacologic trial
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseveredegeneration_to_ventricular_fibrillation
    Pre-excited AF/flutter degenerating to ventricular fibrillation or polymorphic VT — the feared mechanism of sudden death in WPW
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalsevereinadvertent_av_nodal_blocker_administered
    Adenosine, IV diltiazem/verapamil, beta-blocker, digoxin or IV amiodarone given to a patient with pre-excited AF/flutter — high risk of acceleration to VF
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverehigh_risk_accessory_pathway_short_pre_excited_rr
    Shortest pre-excited R-R interval in AF <250 ms, multiple accessory pathways, or syncope/arrest as the presentation — markers of a high-risk pathway with elevated SCD risk
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalsevererecurrent_pre_excited_tachyarrhythmia_storm
    Repeated pre-excited AF/flutter episodes requiring multiple cardioversions within a short period — electrical storm in the pre-excited substrate
    Trigger could not be auto-evaluated — needs clinician judgement.

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Recommended regimen

Pre-excited atrial flutter — synchronised DCCV if unstable; IV procainamide/ibutilide if stable; AV-nodal blockers ABSOLUTELY contraindicated (2015 ACC/AHA/HRS SVT; 2019 ESC SVT; 2020 ESC AF)
axis: pre_excited_flutter_dccv_or_pathway_prolonging_drug_no_av_nodal_blockers
Selected axis "Pre-excited atrial flutter — synchronised DCCV if unstable; IV procainamide/ibutilide if stable; AV-nodal blockers ABSOLUTELY contraindicated (2015 ACC/AHA/HRS SVT; 2019 ESC SVT; 2020 ESC AF)" by default fallback (first axis)
  • Synchronised DC cardioversion
    first line
    electrical_therapy
    100-200 J biphasic synchronised, escalate as needed (immediate if unstable; default even in many stable patients given VF risk) • N/A • as needed; immediate if haemodynamic instability
    triggers: haemodynamic_instability, failed_or_contraindicated_pharmacologic_rhythm_control, degeneration_to_vf_use_unsynchronised_defibrillation
    ACLS 2020 + SVT guidelines — definitive, fastest, safest termination; avoids the VF risk of AV-nodal blockade entirely
  • procainamide
    first line
    class_ia_antiarrhythmic
    15-17 mg/kg IV at ≤20-50 mg/min until arrhythmia terminates, hypotension, QRS widens >50%, or max dose; then 1-4 mg/min infusion • IV • loading then infusion, monitored
    triggers: stable_pre_excited_flutter_pharmacologic_strategy
    2015 ACC/AHA/HRS + 2019 ESC SVT — prolongs accessory-pathway refractoriness and slows pre-excited conduction; preferred stable-patient agent; stop for hypotension or >50% QRS widening
    rxcui 8700
  • ibutilide
    second line
    class_iii_antiarrhythmic
    1 mg IV over 10 min (0.01 mg/kg if <60 kg), may repeat once after 10 min; continuous ECG ≥4 h • IV • once, may repeat ×1
    triggers: stable_pre_excited_flutter_procainamide_unavailable_or_unsuitable
    2019 ESC SVT — effective for pre-excited AF/flutter; correct K/Mg first; torsades risk → monitor QT ≥4 h with defibrillator available
    rxcui 41289
  • AVOID adenosine
    contraindication substitute
    do_not_use
    DO NOT GIVE • N/A • N/A
    triggers: pre_excited_atrial_flutter_or_af
    Transient AV-nodal block can increase antegrade accessory-pathway conduction and precipitate AF→VF; contraindicated in pre-excited AF/flutter (2015 ACC/AHA/HRS)
  • AVOID IV diltiazem/verapamil + beta-blockers
    contraindication substitute
    do_not_use
    DO NOT GIVE • N/A • N/A
    triggers: pre_excited_atrial_flutter_or_af
    AV-nodal blockade preferentially channels conduction down the accessory pathway → very rapid ventricular rates and VF; contraindicated (2019 ESC SVT; 2020 ESC AF)
  • AVOID digoxin
    contraindication substitute
    do_not_use
    DO NOT GIVE • N/A • N/A
    triggers: pre_excited_atrial_flutter_or_af
    Shortens accessory-pathway refractory period and slows the AV node → accelerated pre-excited conduction; contraindicated
  • AVOID intravenous amiodarone
    contraindication substitute
    do_not_use
    DO NOT GIVE acutely • N/A • N/A
    triggers: pre_excited_atrial_flutter_or_af
    IV amiodarone can cause AV-nodal block + hypotension and has been associated with acceleration to VF in pre-excited AF — avoided acutely per 2019 ESC SVT / 2020 ESC AF (DCCV or procainamide preferred)
  • Accessory-pathway catheter ablation (definitive)
    rescue
    electrophysiology_procedure
    EP study + radiofrequency/cryo ablation of the accessory pathway; confirm bidirectional block • N/A • definitive, post-stabilisation
    triggers: post_pre_excited_af_or_flutter_event, high_risk_pathway_short_pre_excited_rr
    2015 ACC/AHA/HRS + 2019 ESC SVT — Class I after a pre-excited AF/flutter event; curative and removes the VF substrate

outpatient playbook — drug actions (2)

  1. 1. post-successful-ablation: no chronic antiarrhythmic needed
    none if pathway eliminated • N/A • N/A
    trigger: Successful ablation with bidirectional block
    Ablation is curative; AV-nodal-blocker restriction lifted once pathway confirmed gone
  2. 2. if ablation deferred: EP-directed rhythm strategy + strict AV-nodal-blocker avoidance
    rxcui 8814
    EP-directed (e.g., flecainide/propafenone if no structural disease) — never an AV-nodal blocker • PO • per EP
    trigger: Ablation declined/deferred
    2019 ESC SVT — pathway-non-AV-nodal strategy while pathway persists

Auto-drafted A&P note

outpatient

Subjective

- Possible entry pathways: Palpitations, presyncope or syncope in a patient with known WPW / a delta wave on prior ECG — pre-excited atrial flutter/AF until proven otherwise (VF risk); Very fast (>200-250 bpm), broad-complex, often irregular tachycardia — pre-excited atrial flutter/AF; distinguish from polymorphic VT and SVT with aberrancy; ECG showing flutter/fibrillatory atrial activity conducting with variable broad pre-excited QRS morphology — antegrade accessory-pathway conduction.

Objective

- No vitals, labs, or imaging entered for this encounter.

Assessment

**Pre-excited atrial flutter (WPW) — DCCV / procainamide; AV-nodal blockers ABSOLUTELY contraindicated** (cardio.atrial_flutter.wpw-preexcited.v1).
Scope: Pre-excited atrial flutter = flutter/AF conducting antegrade down a non-decremental accessory pathway → potentially very rapid broad tachycardia that can degenerate to VF. The single most important rule: NO AV-nodal blockers (adenosine, IV diltiazem/verapamil, beta-blockers, digoxin, IV amiodarone)

No severity triggers fired against current inputs.

Plan

Regimen axis: **Pre-excited atrial flutter — synchronised DCCV if unstable; IV procainamide/ibutilide if stable; AV-nodal blockers ABSOLUTELY contraindicated (2015 ACC/AHA/HRS SVT; 2019 ESC SVT; 2020 ESC AF)**.
1. Synchronised DC cardioversion 100-200 J biphasic synchronised, escalate as needed (immediate if unstable; default even in many stable patients given VF risk) N/A as needed; immediate if haemodynamic instability (electrical_therapy, first line) — ACLS 2020 + SVT guidelines — definitive, fastest, safest termination; avoids the VF risk of AV-nodal blockade entirely
2. procainamide 15-17 mg/kg IV at ≤20-50 mg/min until arrhythmia terminates, hypotension, QRS widens >50%, or max dose; then 1-4 mg/min infusion IV loading then infusion, monitored (class_ia_antiarrhythmic, first line) — 2015 ACC/AHA/HRS + 2019 ESC SVT — prolongs accessory-pathway refractoriness and slows pre-excited conduction; preferred stable-patient agent; stop for hypotension or >50% QRS widening
3. ibutilide 1 mg IV over 10 min (0.01 mg/kg if <60 kg), may repeat once after 10 min; continuous ECG ≥4 h IV once, may repeat ×1 (class_iii_antiarrhythmic, second line) — 2019 ESC SVT — effective for pre-excited AF/flutter; correct K/Mg first; torsades risk → monitor QT ≥4 h with defibrillator available
4. AVOID adenosine DO NOT GIVE N/A N/A (do_not_use, contraindication substitute) — Transient AV-nodal block can increase antegrade accessory-pathway conduction and precipitate AF→VF; contraindicated in pre-excited AF/flutter (2015 ACC/AHA/HRS)
5. AVOID IV diltiazem/verapamil + beta-blockers DO NOT GIVE N/A N/A (do_not_use, contraindication substitute) — AV-nodal blockade preferentially channels conduction down the accessory pathway → very rapid ventricular rates and VF; contraindicated (2019 ESC SVT; 2020 ESC AF)
6. AVOID digoxin DO NOT GIVE N/A N/A (do_not_use, contraindication substitute) — Shortens accessory-pathway refractory period and slows the AV node → accelerated pre-excited conduction; contraindicated
7. AVOID intravenous amiodarone DO NOT GIVE acutely N/A N/A (do_not_use, contraindication substitute) — IV amiodarone can cause AV-nodal block + hypotension and has been associated with acceleration to VF in pre-excited AF — avoided acutely per 2019 ESC SVT / 2020 ESC AF (DCCV or procainamide preferred)
8. Accessory-pathway catheter ablation (definitive) EP study + radiofrequency/cryo ablation of the accessory pathway; confirm bidirectional block N/A definitive, post-stabilisation (electrophysiology_procedure, rescue) — 2015 ACC/AHA/HRS + 2019 ESC SVT — Class I after a pre-excited AF/flutter event; curative and removes the VF substrate

Setting playbook (outpatient) — Definitive cure via ablation and post-ablation clearance; long-term surveillance only if ablation deferred/incomplete; family screening where indicated
9. post-successful-ablation: no chronic antiarrhythmic needed none if pathway eliminated N/A N/A — Successful ablation with bidirectional block (Ablation is curative; AV-nodal-blocker restriction lifted once pathway confirmed gone)
10. if ablation deferred: EP-directed rhythm strategy + strict AV-nodal-blocker avoidance EP-directed (e.g., flecainide/propafenone if no structural disease) — never an AV-nodal blocker PO per EP — Ablation declined/deferred (2019 ESC SVT — pathway-non-AV-nodal strategy while pathway persists)

Non-pharmacologic actions:
- Confirm pre-excitation resolved post-ablation
- Lift activity restriction only after cure/reassuring risk stratification
- Family screening for pre-excitation if SCD history
- Remove drug-avoidance flag only when pathway eliminated

AVOID / contraindication checks:
- Absolute_contraindication_adenosine_in_pre_excited_af_or_flutter
- Absolute_contraindication_iv_diltiazem_verapamil_in_pre_excited_af_or_flutter
- Absolute_contraindication_beta_blocker_in_pre_excited_af_or_flutter
- Absolute_contraindication_digoxin_in_pre_excited_af_or_flutter
- Avoid_iv_amiodarone_acutely_in_pre_excited_af_or_flutter
- Correct_potassium_and_magnesium_before_ibutilide (torsades risk)
- Stop_procainamide_for_hypotension_or_qrs_widening_above_50pct
- Procainamide_renal_dose_adjust_napa_accumulation_in_ckd
- Decision:synchronised_dccv_immediately_if_haemodynamically_unstable
- Decision:dccv_preferred_even_in_many_stable_patients_given_vf_risk
- Decision:procainamide_or_ibutilide_first_line_pharmacologic_if_stable
- Decision:accessory_pathway_ablation_class_i_after_pre_excited_af_or_flutter
- Decision:sports_occupational_clearance_only_after_ablation_or_reassuring_risk_stratification

Monitoring

Regimen monitoring:
- continuous telemetry for recurrence or vf with defibrillator at bedside
- shortest pre excited rr documented as arrhythmic risk marker
- qt monitoring at least 4h if ibutilide used
- bp and qrs width continuously during procainamide loading
- electrolyte normalisation potassium and magnesium
- post cardioversion rhythm and neuro checks
- ep study risk stratification then ablation outcome bidirectional block

Setting (outpatient) monitoring:
- Post-ablation ECG + symptom surveillance
- Periodic review only if ablation deferred
- Family screening completion

Follow-up plan: Electrophysiology: accessory-pathway ablation (curative; Class I post pre-excited AF/flutter) — confirm bidirectional pathway block; sports/occupational clearance only after successful ablation or reassuring risk stratification; family screening if SCD history; document lifelong AV-nodal-blocker avoidance until pathway eliminated; anticoagulation per CHA2DS2-VASc if AF component persists
- Close-out criterion: ablation completed/scheduled + clearance + avoidance documentation in place

Monitoring phase: Continuous telemetry for recurrence/VF; post-cardioversion rhythm and neuro checks; QT monitoring if ibutilide used (torsades risk, watch ≥4 h); electrolyte normalisation; readiness for repeat DCCV

Disposition

Current setting: outpatient — Definitive cure via ablation and post-ablation clearance; long-term surveillance only if ablation deferred/incomplete; family screening where indicated

Disposition criteria:
- Discharge from cardiology after confirmed cure; longitudinal EP follow-up only if pathway persists

Escalation triggers (move to higher acuity):
- Recurrence post-ablation → repeat EP study
- New symptoms if deferred → re-offer ablation
- Family member with high-risk pathway → refer

Earlier-Return Triggers

Return-precaution thresholds (watch for):
- [SEVERE] Pre-excited atrial flutter/AF with hypotension, shock, ischaemia, pulmonary oedema or depressed consciousness — immediate synchronised DC cardioversion is mandatory; no time for pharmacologic trial
- [SEVERE] Pre-excited AF/flutter degenerating to ventricular fibrillation or polymorphic VT — the feared mechanism of sudden death in WPW
- [SEVERE] Adenosine, IV diltiazem/verapamil, beta-blocker, digoxin or IV amiodarone given to a patient with pre-excited AF/flutter — high risk of acceleration to VF

Citations

- 2015 ACC/AHA/HRS SVT Guideline + 2019 ESC SVT Guideline + 2020 ESC AF Guideline + 2017 AHA/ACC/HRS VA/SCD [PMID:26399663](https://pubmed.ncbi.nlm.nih.gov/26399663/)
- Cited evidence (PMID 31504425) [PMID:31504425](https://pubmed.ncbi.nlm.nih.gov/31504425/)
- Cited evidence (PMID 32860505) [PMID:32860505](https://pubmed.ncbi.nlm.nih.gov/32860505/)
- Cited evidence (PMID 29097296) [PMID:29097296](https://pubmed.ncbi.nlm.nih.gov/29097296/)
- Cited evidence (PMID 25085292) [PMID:25085292](https://pubmed.ncbi.nlm.nih.gov/25085292/)

Last reconciled with current guidelines: 2026-05-15.
References