Arrhythmias:
zero-to-safe.
The monitor can be dramatic. Your first move should be boring on purpose: pulse → causal instability → QRS width → regularity → mechanism. That sequence keeps the first action safe while the diagnosis is still blurry.
ARR-01 progress
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How this chapter teaches
Knowing it once is not the same as finding it at 02:00.
You already know how to learn. The problem is access: can the right model show up, under pressure, after time has passed? ARR-01 uses retrieval and explanation—not rereading as a personality test.
- 01Retrieve first
Commit the syndrome and next move before opening the answer.
- 02Explain the why
Connect channel, tissue, physiology, and patient substrate to the bedside effect.
- 03Name the boundary
Say which clue, comorbidity, uncertainty, or harm would change the plan.
- 04Transfer it
Use the same model in a different lens and a less familiar patient.
Why this design—and where the evidence stops
A 2024 health-professions systematic review found benefits in 43 of 63 distributed/retrieval-practice experiments, although interventions and assessments were heterogeneous. A 2024 meta-analysis found modest knowledge benefit for spaced online education and a larger signal for clinical-behavior change, with risk-of-bias limitations. Self-explanation improves clinical-reasoning transfer when prompts require active processing rather than passive exposure.
Design inference: spacing, retrieval, mechanism explanation, and changed-context cases are the default. The exact intervals above are a practical schedule—not a biologic law. Difficulty should remain productive: effortful enough to strengthen retrieval, not so opaque that it becomes guessing.
The monitor says “VT.” The blood pressure says now.
A 68-year-old with ischemic cardiomyopathy becomes confused and diaphoretic. Pulse 184/min, blood pressure 74/42 mm Hg. The rhythm is regular and wide. You have IV access, pads are going on, and the patient still has a pulse.
What is the decision?
Synchronize now. Why — the organized tachycardia is plausibly driving shock. What changes the branch — polymorphism or pulse loss requires unsynchronized energy.The master decision tree
Pulse → instability → width → regularity.
Say the syndrome before the drug: unstable regular wide-complex tachycardia with a pulse. The ECG may be yelling; this sentence keeps you from yelling a medication back at it.
Think AVNRT/AVRT, atrial tachycardia, flutter with fixed conduction, or sinus tachycardia.
For a stable regular narrow tachycardia: modified Valsalva first, then adenosine when appropriate. Ask whether the rhythm is AV-node-dependent or whether adenosine will only reveal atrial activity.
Think AF, flutter with variable conduction, MAT, or frequent ectopy.
Choose rate/rhythm therapy from ventricular function, pressure, congestion, sympathetic state, duration, anticoagulation context, and the precipitating illness.
Treat uncertain wide-complex tachycardia as VT until a safer explanation is established.
Stable regular monomorphic WCT may receive an antiarrhythmic infusion and expert consultation. Adenosine is confined to stable, regular, monomorphic WCT when an AV-node-dependent mechanism is plausible.
Pause: polymorphic VT, pre-excited AF, AF with aberrancy, toxicity, and artifact live here.
Do not reflexively give an AV-nodal blocker. In pre-excited AF it can favor accessory-pathway conduction; sustained polymorphic VT requires immediate unsynchronized shock.
Mechanism anchor
A wide QRS is a warning label, not a diagnosis.
Think of width as the ventricular delivery route. Narrow usually means activation used the native conduction highway. Wide means it took a detour—or started in the ventricle. The detour does not name the rhythm, but it raises the cost of the wrong drug.
Regularity tells you how many clocks are arguing.
A regular rhythm suggests one repeating circuit or focus. Irregularity can reveal competing atrial wavefronts, variable AV conduction, changing ventricular activation, or polymorphism. That is why a drug that fits AVNRT can be useless—or dangerous—one branch over.
One case · four lenses
Same rhythm. Four different jobs.
Switch lenses on the opening case. Each lens changes the accountable work, the clock, the likely failure, and the handoff—not just the vocabulary.
Make the next intervention executable and intercept medication-system failure before administration.
- Name the syndrome, not a fragile diagnosis.“Unstable regular wide-complex tachycardia with a pulse” is enough to act safely.
- Build and verify the electrical plan.Confirm sync markers, pads, energy strategy, sedation feasibility, airway support, and the post-conversion branch.
- Prepare the rescue branch.Sustained polymorphic VT → immediate unsynchronized shock. Pulse loss → start CPR and follow arrest rhythm analysis; defibrillate VF/pVT.
- Own the last safe medication mile.Prioritize high-risk orders; verify selection, dose, concentration, route, pump strategy, compatibility, monitoring, and stop rules before the drug enters the line.
Turn a successful conversion into a coherent daily plan, then a safe transition the next team and patient can actually follow.
- Reconstruct the trigger and substrate.Ischemia, scar, HF decompensation, infection, thyroid disease, sleep apnea, electrolyte loss, alcohol, stimulant exposure, and medication changes.
- Reconcile every indication.Separate acute rescue from chronic prevention, resolve duplications and interactions, and avoid therapeutic inertia after the reason for a drug changes.
- Reassess the whole regimen daily.Specify rhythm endpoints, QT/QRS thresholds, electrolyte targets, renal/hepatic reassessment, adherence barriers, and what finding triggers escalation or de-escalation.
- Close the transition.Document the cardiology/EP plan, anticoagulation logic, monitoring ownership, patient teach-back, access, and the exact follow-up question.
Ask whether the arrhythmia is the driver of shock, a consequence of shock, or both—and re-answer as the physiology changes.
- Interrogate hemodynamics.Preload, contractility, vascular tone, RV/LV function, mechanical support, ventilator effects, catecholamine exposure, and perfusion markers.
- Model changing PK/PD.Low hepatic flow, AKI/CRRT, acidemia, altered protein binding, cumulative infusions, and active metabolites can change effect within hours.
- Reduce the arrhythmogenic environment.Treat ischemia, hypoxia, acidosis, fever, agitation, pain, electrolyte loss, and unnecessary sympathomimetics or QT/QRS-active drugs.
- Plan, document, and debrief recurrence.Defibrillation readiness, pacing, sedation/sympathetic control, EP escalation, mechanical support, handoff, and medication-safety learning after the event.
Explain what circuit or focus exists, why this patient developed it, and which diagnostic or procedural decision changes the trajectory.
- Build the differential from anatomy.Ventricular scar re-entry, SVT with aberrancy, pre-excitation, focal automaticity, triggered activity, drug/toxin effect, and metabolic conduction delay.
- Use ECG findings as likelihood modifiers.AV dissociation, capture/fusion, concordance, axis, morphology, prior BBB, and comparison with baseline—without pretending any one algorithm is absolute.
- Choose definitive diagnostics.Post-conversion ECG, echo, ischemic workup, medication/toxin history, family history, CMR, ambulatory monitoring, genetics, or EP study as the case warrants.
- Define the endpoint.Acute termination, recurrence suppression, ablation, device therapy, substrate treatment, prognosis, and shared decisions.
What the practice standards changed in these lenses
The shared floor is comprehensive medication management: assess the patient and medication problem, build and implement a collaborative plan, follow outcomes, communicate, and keep developing competence. Specialty changes what must happen first and what failure is most costly.
ASHP emphasizes resuscitation presence, prospective interception of high-risk medication errors, medication preparation/administration support, toxicology, order triage, discharge work, quality improvement, education, and research.
The BCPS/general clinical-pharmacy frame emphasizes patient-centered plans, evidence appraisal, repeated monitoring/modification, communication, education, medication-use systems, and transitions across a broad adult population.
The ASHP–ACCP–SCCM position and BCCCP outline add daily interdisciplinary rounds, dynamic PK/PD, devices and organ support, resuscitation, stewardship, ICU medication safety, quality analytics, and ICU-to-ward transitions.
This remains a deliberate counter-lens: diagnostic synthesis, procedural eligibility, prognosis, and shared decisions. It is not presented as a pharmacy board-certification domain.
Credential boundary: BCPS is the current broad pharmacotherapy baseline. BCCCP supplies the critical-care specialization. BPS has published a validated BCEMP outline effective December 1, 2026; until then, it is a forthcoming specialty blueprint, not a credential the learner is expected already to hold.
- ACCP Standards of Practice · 2014
- ACCP Clinical Pharmacist Competencies · 2017
- ASHP Emergency Medicine Pharmacist Services · 2021
- BPS BCPS examination specifications · 2024
- BPS BCCCP examination specifications · 2024
- BPS BCEMP examination specifications · effective December 2026
- ASHP–ACCP–SCCM critical care position · 2020
Interactive · rhythm-to-action
Choose the next safe move.
Four cases. One rule: choose from the patient plus the tracing—never the tracing alone. These strips are schematic, not diagnostic.
Emergency department
Loading case…
Drug atlas preview
Mechanism is a safety tool.
These are memory anchors. The full mechanism-to-bedside monograph for every agent now lives in the antiarrhythmic drug atlas—the first deep-dive module off this chapter.
Open the antiarrhythmic drug atlas
Open the pharmacology workbenchFour safety sketches · EHRA compendium close read
Adenosine
The AV node’s circuit breaker—not a universal reset button. It fits AV-node-dependent regular SVT and may expose atrial activity. Irregular, polymorphic, or pre-excited rhythms are a different electrical panel.
Half-life measured in seconds · give with a continuous rhythm strip and a defibrillator at hand · expect transient AF or brief proarrhythmia at conversion · caffeine/theophylline oppose · dipyridamole potentiatesProcainamide
It slows conduction and lengthens refractoriness. Useful in selected stable monomorphic VT or pre-excited AF; pressure, HF, QRS/QT, kidney function, and cumulative dose decide whether the runway is long enough.
Parent + active metabolite · renal accumulation · explicit stop rulesAmiodarone
The electrophysiology Swiss Army knife—with a storage-unit lease. Broad utility does not erase IV hypotension, conversion risk, tissue persistence, interactions, or chronic organ toxicity.
IV and chronic pharmacology differ · CYP/P-gp interactions · very large VdMagnesium
Not seasoning for every ugly tracing. It may be considered for recurrent polymorphic VT with long QT; pair it with trigger removal and potassium correction, and keep the evidence limits visible.
2025 AHA Class 2b, C-LD · direct randomized torsades evidence is absentLead pharmacology source · corrected
Read antiarrhythmics as behavior—not a class list.
The 2025 EHRA practical compendium is the pharmacology spine for this deep dive. Its best move is connecting channel state, rate, tissue, substrate, PK, interactions, and proarrhythmia to what you monitor at the bedside.
Use dependence
Flecainide binds activated/inactivated sodium channels and dissociates slowly. Faster activation means accumulating block: useful against tachycardia, visible as rate-related QRS widening, and dangerous when substrate or conduction reserve is wrong.
Bedside tell → QRS behavior during loading or faster ratesReverse use dependence
Sotalol and dofetilide prolong repolarization more at slower rates. Conversion can remove the tachycardia and reveal the hazard: pauses, longer QT, early afterdepolarizations, torsades.
Bedside tell → QT after conversion, pauses, K/Mg, renal functionPK becomes electrophysiology
Renal decline can turn yesterday’s tolerated exposure into today’s conduction or repolarization problem. Tissue storage and active metabolites can make the offset far slower than the infusion or prescription suggests.
Bedside tell → organ trajectory, cumulative dose, active metabolitesInteractions become rhythm
CYP and P-gp inhibition can raise antiarrhythmic or companion-drug exposure; stacked AV-node block or QT activity can be intentional—or the mechanism of harm.
Bedside tell → full regimen, anticoagulants, rate agents, QT stack- What tissue and mechanism am I trying to alter?
- What rate or channel state strengthens the drug?
- What substrate makes that same effect unsafe?
- How will this patient clear, store, or interact with it?
- What ECG, hemodynamic, laboratory, and clinical stop rule will reveal failure first?
Closed-book check: explain the paradox
Retrieve first: Why can a sodium-channel blocker become more powerful during tachycardia while a potassium-channel blocker becomes more proarrhythmic after conversion?
Reveal expert response
Fast activation increases occupancy of activated/inactivated sodium channels when dissociation is slow—use dependence. Slower rates and pauses amplify repolarization prolongation from some IKr blockers—reverse use dependence. The monitoring target therefore changes with rate and with the moment of conversion.
Source-to-practice lab
Read the paper without drowning in it.
Find the decision, do the absolute math, name the transfer limit, then defend the bedside move. Open one card or all of them; journal club does not need to become a hostage situation.
Open the literature labThree trial figures · 10 reading cards · 6 media resources
- 01OrientRead the tertiary scaffold.
- 02InterrogateInspect methods and the exact excerpt.
- 03QuantifyRead absolute effects and uncertainty.
- 04TransferName who the result does—and does not—fit.
- 05Teach backDefend the bedside decision without looking.
Rounds pass
Read the result and practice boundary on the tertiary, AHA, REVERT, and PROCAMIO cards.
Journal-club pass
Add methods, confidence intervals, and each teach-back before opening the full paper.
Full nerd mode
Read every card, then transfer the evidence across ED, ICU, medicine, and physician decisions.
Figure lab 01 · original visualization
Three trials, three different questions.
Start with denominators. Then read the absolute effect, harm, and transfer boundary. A larger bar is not automatically a stronger or more transferable conclusion.
- Intervention
- Comparator
- Worse outcome
- Colour tracks the outcome, not the drug — the same agent can be the safer choice in one row and the harm in another.
Technique changes the effect.
- Absolute benefit
- 26 percentage points
- Approximate NNT
- 4
- Adjusted OR
- 3.7 (95% CI 2.3–5.8)
Read benefit and harm together.
Major cardiac adverse events
Tachycardia terminated by 40 minutes
Near-equal totals can conceal different workflows.
- Absolute difference
- 4 points (95% CI 0–9)
- Drug alone converted
- 52%
- Strategy p value
- 0.07
| Trial | Population | Endpoint | Comparison | Result |
|---|---|---|---|---|
| REVERT | Stable adult SVT | Sinus rhythm at 1 minute | Modified vs standard Valsalva | 43% vs 17% |
| PROCAMIO | Tolerated regular WCT | Major cardiac adverse events | Procainamide vs amiodarone | 9% vs 41% |
| PROCAMIO | Tolerated regular WCT | Termination by 40 minutes | Procainamide vs amiodarone | 67% vs 38% |
| RAFF2 | Selected stable acute AF | Conversion to sinus rhythm | Drug–shock vs shock-only | 96% vs 92% |
Commit an interpretation before revealing the debrief
REVERT: the clinically useful measure is the 26-point absolute benefit and NNT near 4—not a claim that every SVT is 3.7 times more likely to convert.
PROCAMIO: both the adverse-event and termination signals favor procainamide, but the sample is small and the transfer boundary excludes unstable, polymorphic, and pulseless rhythms.
RAFF2: both bundled strategies converted most eligible patients. A nonsignificant 4-point difference is not proof of equivalence; workflow, sedation, preference, and eligibility still matter.
verified excerpts · each 20 words or fewer
Key reading cards
0 reading cards marked complete.
01 Wide QRS Complex TachycardiaTertiary scaffold · Foundation
“Wide complex tachycardia is a dysrhythmia with a long list of potential causes”
Continuing Education Activity · 13 quoted words
- A wide-complex tachycardia has a long differential; treat it as VT until a safer explanation is proven.
- Width and regularity are probability-changing features, not a final diagnosis.
A broad, open-access clinical review that organizes the differential before the learner enters individual trials and guidelines.
No comparative effect estimate; its job is orientation, vocabulary, and differential diagnosis.
Start with patient stability, then treat width and regularity as probability-changing features rather than a final diagnosis.
Tertiary reviews compress nuance and can age. Verify management-changing claims against the current guideline and direct evidence below.
Teach-back prompt
Retrieve first: Name four causes of wide-complex tachycardia that would change the medication plan.
Reveal expert response
Examples include ventricular tachycardia, pre-excited AF, sodium-channel blockade, hyperkalemia, SVT with aberrancy, pacing, and artifact. The point is to connect each cause to a different hazard or rescue pathway.
02 Sustained polymorphic ventricular tachycardiaCurrent guideline · ED + ICU
“Polymorphic ventricular tachycardia is always unstable and should be treated immediately with defibrillation”
Adult ALS: polymorphic VT discussion · 13 quoted words
- Sustained polymorphic VT is treated as unstable: immediate unsynchronized shock (Class 1, B-NR).
- Magnesium for recurrent long-QT torsades is Class 2b, C-LD; the guideline notes randomized drug evidence is absent.
- Beat-to-beat QRS variation defeats reliable synchronization.
Current emergency guidance derived from systematic, scoping, and focused evidence reviews.
Immediate unsynchronized shock for sustained polymorphic VT is Class 1, B-NR. Magnesium for recurrence with long QT is Class 2b, C-LD.
Shock sustained polymorphic VT without waiting for synchronization, even when a pulse is present; address the substrate after energy.
A recommendation is not a randomized comparison. The guideline notes that randomized evidence for drug management of polymorphic VT is absent.
Teach-back prompt
Retrieve first: Why is this an unsynchronized-shock pathway, and what additional action begins if the patient loses a pulse?
Reveal expert response
Beat-to-beat QRS variation makes reliable synchronization impractical. If pulse loss occurs, begin CPR and follow arrest rhythm analysis; defibrillate VF or pulseless VT.
03 When atrial fibrillation is causing instabilityCurrent guideline · ED + physician
“In patients with hemodynamic instability attributable to AF, immediate electrical cardioversion should be performed to restore sinus rhythm”
Electrical cardioversion recommendations · 18 quoted words
- When AF is causing instability, immediate synchronized cardioversion (Class 1, C-LD).
- The causal word matters: AF can be the driver, or a marker of sepsis, PE, or ACS.
- Cardioversion does not replace simultaneous evaluation of the shock state.
Multidisciplinary evidence synthesis for adults across the atrial-fibrillation continuum.
Immediate synchronized cardioversion when instability is attributable to AF is Class 1, C-LD.
The causal word matters: treat AF immediately when it is driving the instability.
AF can also be a marker of sepsis, hemorrhage, PE, ACS, or another shock state. Cardioversion does not replace simultaneous causal evaluation.
Teach-back prompt
Retrieve first: A septic patient has AF at 160/min and hypotension. What observations would make AF more likely to be the driver rather than a compensatory response?
Reveal expert response
Look for temporal coupling, disproportionate rate, loss of atrial contribution in a preload-dependent patient, worsening with rhythm onset, and hemodynamic improvement with rate/rhythm intervention—while treating sepsis in parallel.
04 Flecainide and use dependenceExpert pharmacology synthesis · Pharmacology
“This use-dependent property enables flecainide to effectively block the activation front, contributing to the termination of atrial fibrillation”
Flecainide: use-dependent sodium-channel block · 18 quoted words
- Use dependence: sodium-channel block accumulates at fast rates because there is less diastolic time to dissociate.
- It shows up as rate-related QRS widening during loading or exertion.
- The same property is why flecainide is confined to structurally normal hearts.
Expert consensus integrating ion-channel mechanisms, PK/PD, selection, monitoring, interactions, and proarrhythmia.
This is a mechanistic statement, not a comparative clinical effect estimate.
At faster activation rates, less time is available for flecainide to dissociate from sodium channels, strengthening blockade.
The same mechanism can cause rate-related QRS widening and proarrhythmia. Mechanistic plausibility does not erase patient-selection restrictions.
Teach-back prompt
Retrieve first: What would exercise-related QRS widening reveal about flecainide’s channel-binding behavior?
Reveal expert response
It demonstrates use dependence: faster rates increase the fraction of blocked channels because there is less diastolic time for drug dissociation.
05 Sotalol and reverse use dependenceExpert pharmacology synthesis · Pharmacology + monitoring
“reverse use dependence describes the phenomenon where the effectiveness of a drug is greater at lower heart rates”
Proarrhythmia: reverse use dependence · 18 quoted words
- Reverse use dependence: IKr block prolongs the QT most at slow rates and pauses.
- So torsades risk is highest just after conversion; watch post-conversion QT, K/Mg, and renal function.
Expert consensus connecting antiarrhythmic mechanisms, rate, PK/PD, monitoring, interactions, and proarrhythmia.
No comparative effect estimate; this is a mechanism and monitoring synthesis.
After conversion or during bradycardia and pauses, some IKr blockers can prolong repolarization more strongly, shifting attention to post-conversion QT, electrolytes, and renal exposure.
Not every potassium-channel effect behaves identically, and mechanism alone does not quantify an individual patient's torsades risk. Apply current labeling, guideline, and patient-specific monitoring requirements.
Teach-back prompt
Retrieve first: Why can successful conversion make an IKr-blocker safety problem more visible rather than less?
Reveal expert response
The slower rate and pauses after conversion can magnify repolarization prolongation through reverse use dependence. That can expose QT prolongation and early-afterdepolarization risk even though the tachyarrhythmia has ended.
06 REVERT: do the maneuver correctlyPrimary randomized trial · ED pharmacist
“We have shown that a simple, cost-free, well-tolerated postural modification to the standard Valsalva manoeuvre is highly effective”
Discussion · 18 quoted words
- Modified beat standard Valsalva: 43% vs 17% sinus rhythm at one minute.
- Absolute benefit ~26 points, NNT ~4 for a free, repeatable maneuver before any drug.
- Only for stable, regular, narrow SVT; it does not apply to AF, flutter, or wide-complex rhythms.
Multicenter randomized, assessor-blinded trial in 10 UK EDs; 428 primary-analysis encounters with stable SVT.
Sinus rhythm at one minute: 43% modified versus 17% standard; absolute difference 26 percentage points; approximate NNT 4; adjusted OR 3.7 (95% CI 2.3–5.8).
A correctly performed modified Valsalva belongs before adenosine in an appropriate stable regular narrow-complex SVT pathway.
The intervention was not blinded to clinicians or patients and does not apply to instability, AF/flutter, irregular rhythms, or undifferentiated WCT.
Teach-back prompt
Retrieve first: Calculate the absolute benefit and NNT, then name the rhythm and stability checks required before using the result.
Reveal expert response
The absolute benefit is about 26 percentage points and NNT is about 4. Confirm a stable patient with a compatible regular SVT; exclude rhythms and states in which a vagal-first pathway is inappropriate.
07 A newer, smaller Valsalva trialNew primary trial · Evidence critique
“Sinus rhythm was restored in 10 of 38 patients (26.3%) in the modified Valsalva group”
Abstract: Results · 15 quoted words
- A smaller 2026 trial: modified 26.3% vs standard 16.2%, same direction but far less precise.
- The 95% CI spanned harm to large benefit, so it cannot overturn REVERT.
- Not statistically significant is not the same as equivalent.
Single-center, open-label, pragmatic randomized trial in 75 adults with stable PSVT in an Indian tertiary ED.
Modified 26.3% versus standard 16.2%; 95% CI for the absolute difference −8.2% to 28.4%; not statistically significant.
The direction of effect remained favorable, but the estimate was imprecise and smaller than REVERT’s.
A small single-center trial with a confidence interval spanning harm and substantial benefit cannot establish equivalence or erase the larger trial.
Teach-back prompt
Retrieve first: Why does ‘not statistically significant’ fail to prove that the two maneuvers are equivalent?
Reveal expert response
Failure to reject no difference is not proof of equality. The wide confidence interval shows that the study cannot distinguish modest harm, no effect, or clinically important benefit.
08 PROCAMIO: comparative drug evidencePrimary randomized trial · ED + critical care
“Procainamide therapy was associated with less major cardiac adverse events and a higher proportion of tachycardia termination within 40 min”
Abstract: Conclusions · 20 quoted words
- In tolerated wide-QRS tachycardia, procainamide beat amiodarone on major cardiac adverse events: 9% vs 41%.
- It also terminated more: 67% vs 38% by 40 minutes.
- Small (n=62), open-label, with exclusions; do not extend to unstable, polymorphic, or pulseless VT, or to severe HF or long QT.
Multicenter, randomized, open-label comparison; 74 enrolled and 62 analyzed with tolerated regular wide-QRS tachycardia, probably monomorphic VT.
Major cardiac adverse events: 9% procainamide versus 41% amiodarone. Termination by 40 minutes: 67% versus 38%.
For carefully selected tolerated monomorphic WCT, procainamide has stronger direct comparative evidence than amiodarone.
Small, open-label, 12 exclusions from the principal analysis, and not powered for mortality. Do not extrapolate to unstable, polymorphic, or pulseless VT.
Teach-back prompt
Retrieve first: Would you transfer this result to LVEF 15%, SBP 92 mm Hg, CKD, and QTc 510 ms? Defend the plan.
Reveal expert response
No automatic transfer. Hypotension, severe HF, renal accumulation, and prolonged QT narrow or remove the procainamide option; reassess stability and prepare electrical therapy with expert input.
09 RAFF2: two workable acute-AF strategiesPrimary randomized trial · ED pharmacist
“Both the drug-shock and shock-only strategies were highly effective, rapid, and safe in restoring sinus rhythm”
Abstract: Interpretation · 16 quoted words
- Drug-shock 96% vs shock-only 92% conversion; both strategies work in selected recent-onset AF.
- Procainamide alone converted ~52%, often sparing sedation and a shock.
- The 4-point difference (CI 0-9, p=0.07) is not proof of equivalence; workflow and preference decide.
Partial-factorial randomized trial at 11 Canadian academic EDs; 396 selected adults with stable acute AF.
Conversion: 96% drug–shock versus 92% shock-only; absolute difference 4% (95% CI 0–9; p=0.07). Procainamide alone converted 52%.
Either pathway can work for selected stable recent-onset AF; procainamide may avoid sedation and shock in about half.
This compared bundled strategies, did not establish statistical equivalence, and excluded unstable or secondary-AF presentations.
Teach-back prompt
Retrieve first: How should prior response, sedation risk, ED resources, patient preference, and time-to-disposition alter the choice?
Reveal expert response
Use shared, context-specific selection. High sedation risk or limited procedural resources may favor a drug-first attempt; prior drug failure, patient preference, or a need for rapid predictable conversion may favor shock-first when eligible.
10 EAST-AFNET 4: rhythm control as prognosisPrimary randomized trial · Internal medicine
“Early rhythm-control therapy was associated with a lower risk of adverse cardiovascular outcomes than usual care”
Abstract: Conclusions · 16 quoted words
- Early rhythm control lowered cardiovascular events: HR 0.79 (3.9 vs 5.0 per 100 person-years).
- Population was AF within ~1 year of diagnosis plus cardiovascular risk, a prognostic not acute-cardioversion message.
- Rhythm-therapy serious adverse events were higher (4.9% vs 1.4%); it is a strategy, not one drug.
International, randomized, open-label trial with blinded outcome assessment; 2,789 patients with AF diagnosed within one year plus cardiovascular conditions.
Composite event rates: 3.9 versus 5.0 per 100 person-years; HR 0.79 (96% CI 0.66–0.94). Rhythm-therapy-related serious adverse events: 4.9% versus 1.4%.
For selected early-AF patients, rhythm control can be a prognostic strategy rather than symptom rescue alone.
Not an acute ED cardioversion trial. Therapy was heterogeneous, the trial was open-label and stopped early, and the composite cannot be assigned to one drug or ablation.
Teach-back prompt
Retrieve first: Which new AF patients leaving the ED merit an explicit early-rhythm-control referral instead of a rate-control-only plan?
Reveal expert response
Patients within a year of diagnosis who resemble the trial population and have cardiovascular risk or disease merit an intentional rhythm-control discussion, alongside anticoagulation and comorbidity management—not an automatic prescription for one intervention.
Watch · simulate · inspect
A curated media shelf, with a job for every click.
These are outbound resources, not endorsements of every statement they contain. Predict before opening; teach back afterward. Current guidance outranks an older demonstration when they differ.
Modified Valsalva Maneuver
JAMA Network / JN Learning
- Before opening
- Predict the exact strain, repositioning, and leg-raise sequence before pressing play.
- Afterward
- Teach the maneuver back as an executable order, including patient selection and monitoring.
Access: Public player; an auto-generated transcript is available but may contain errors.
Boundary: Copyrighted AMA content. Link out only; do not copy, download, or embed.
Link checked 2026-07-16Synchronised cardioversion
Resuscitation Council UK
- Before opening
- Name the four setup checks you expect before shock delivery.
- Afterward
- Identify the sync-marker, safety, sedation, and re-synchronization steps shown.
Access: Full transcript and contrast controls are available.
Boundary: The older 120-J example is a device/scenario demonstration, not a universal current energy recommendation; pair it with the 2025 AHA algorithm.
Link checked 2026-07-16Manual External Defibrillation, Cardioversion, and Pacing
University of Florida Center for Safety, Simulation & Advanced Learning Technologies
- Before opening
- Write the device sequence for synchronized cardioversion from memory.
- Afterward
- Repeat locally using the text pathway: pads → rhythm → sync → energy → clear → shock → reassess → re-sync if needed.
Access: Free non-CME WebGL simulator; desktop-oriented and drag-heavy. The local text pathway is the keyboard alternative.
Boundary: Use for equipment logic, not as a substitute for device-specific training or current protocols.
Link checked 2026-07-16Marion-Arnsdorf ECG Project
University of Chicago Medicine
- Before opening
- Choose one mechanism—automaticity, triggered activity, or re-entry—and sketch it first.
- Afterward
- Explain how that mechanism predicts onset, regularity, response to AV-nodal blockade, and recurrence.
Access: JavaScript is required. Learning units combine electrophysiology diagrams with rhythm examples.
Boundary: No reuse license was visible; link to the original rather than copying its images.
Link checked 2026-07-16Arrhythmia Quiz
University of Utah ECG Learning Center
- Before opening
- Use the same sequence every time: rate → regularity → P–QRS relation → width → patient context.
- Afterward
- Record one morphology clue you over-weighted and one clinical clue you under-weighted.
Access: Image-based questions include AVNRT, AF, flutter, VT, and a ladder diagram.
Boundary: Licensed CC BY-ND-NC; link-only avoids creating an unauthorized derivative.
Link checked 2026-07-162025 Electrical Cardioversion Algorithm
American Heart Association
- Before opening
- Predict the starting-energy rows and the point at which synchronization no longer applies.
- Afterward
- Turn the algorithm into a bedside preparation checklist rather than memorizing one number.
Access: Graphic PDF plus a linked long-description companion.
Boundary: Confirm the specific defibrillator’s recommended energy and local protocol.
Link checked 2026-07-16Baseline assessment · six decisions
Explain the answer you choose.
The clue that changes the plan matters more than the score. Every distractor gets a bedside autopsy: why it fails here, and when it might fit.
Evidence register
The sources behind the calls.
How these are weighed—three visible layers, study design versus recommendation authority, and the questions that decide usefulness—lives on one shared page: how we weigh evidence. Here is the arrhythmias register itself, each record traceable.
Open the full evidence record19 verified source records
seed records · verified links and identifiers
Scope: initial guideline spine and practice-shaping studies. This is a documented scoping set, not yet a completed systematic review.
1 Part 9: Adult Advanced Life Support — 2025 AHA Guidelines for CPR and ECCGuideline · current emergency algorithm · Recommendation-specific
Acute tachyarrhythmia, bradycardia, cardioversion, polymorphic VT, and arrest pathways.
- Citation
- Wigginton JG, et al. Circulation. 2025;152(suppl 2):S538–S577.
- DOI / identifier
- 10.1161/CIR.0000000000001376
2 Part 10: Adult and Pediatric Special Circumstances of Resuscitation — 2025 AHA GuidelinesGuideline · toxicology/special circumstances · Recommendation-specific
Hyperkalemia, pregnancy, pulmonary embolism, and arrhythmogenic drug/toxin emergencies.
- Citation
- Cao D, et al. Circulation. 2025;152(suppl 2):S578–S672.
- DOI / identifier
- 10.1161/CIR.0000000000001380
3 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial FibrillationGuideline · multidisciplinary synthesis · Recommendation-specific
US framework for AF staging, stroke prevention, rate/rhythm control, acute illness, and ablation.
- Citation
- Joglar JA, et al. Circulation. 2024;149:e1–e156.
- DOI / identifier
- 10.1161/CIR.0000000000001193
- Correction / erratum
- Correction DOI 10.1161/CIR.0000000000001207; PMID 38153996.
4 2024 ESC Guidelines for the management of atrial fibrillationGuideline · international synthesis · Recommendation-specific
AF-CARE framework and an explicit international comparison to US recommendations.
- Citation
- Van Gelder IC, et al. Eur Heart J. 2024;45:3314–3414.
- DOI / identifier
- 10.1093/eurheartj/ehae176
- Correction / erratum
- Later correction indexed as PMID 40622753.
5 2018 ACC/AHA/HRS Bradycardia and Cardiac Conduction Delay Guideline — Executive SummaryGuideline · bradycardia/conduction · Recommendation-specific
Sinus node disease, AV block, pacing decisions, and reversible causes.
- Citation
- Kusumoto FM, et al. Circulation. 2019;140:e333–e381.
- DOI / identifier
- 10.1161/CIR.0000000000000627
6 2015 ACC/AHA/HRS Guideline for Adult Supraventricular TachycardiaGuideline · supraventricular tachycardia · Recommendation-specific
AVNRT/AVRT, focal atrial tachycardia, pre-excitation, acute therapy, and ablation.
- Citation
- Page RL, et al. Circulation. 2016;133:e506–e574.
- DOI / identifier
- 10.1161/CIR.0000000000000311
7 2019 ESC Guidelines for Supraventricular TachycardiaGuideline · international comparison · Recommendation-specific
Updated SVT diagnosis, acute treatment, ablation, pregnancy, and special contexts.
- Citation
- Brugada J, et al. Eur Heart J. 2020;41:655–720.
- DOI / identifier
- 10.1093/eurheartj/ehz467
8 2022 ESC Guidelines for Ventricular Arrhythmias and Prevention of Sudden Cardiac DeathGuideline · ventricular arrhythmias · Recommendation-specific
Ventricular arrhythmias, electrical storm, structural disease, genetic evaluation, devices, and ablation.
- Citation
- Zeppenfeld K, et al. Eur Heart J. 2022;43:3997–4126.
- DOI / identifier
- 10.1093/eurheartj/ehac262
9 REVERT: modified versus standard Valsalva for supraventricular tachycardiaRandomized controlled trial · Moderate · direct for stable SVT
Shows why the postural modification belongs before medication in a stable regular narrow-complex pathway.
- Citation
- Appelboam A, et al. Lancet. 2015;386:1747–1753.
- DOI / identifier
- 10.1016/S0140-6736(15)61485-4
10 PROCAMIO: procainamide versus amiodarone for tolerated wide-QRS tachycardiaRandomized controlled trial · Low–moderate · small open-label trial
Practice-shaping comparative evidence, taught with its small sample and setting limitations visible.
- Citation
- Ortiz M, et al. Eur Heart J. 2017;38:1329–1335.
- DOI / identifier
- 10.1093/eurheartj/ehw230
11 RAFF2: electrical versus drug–shock cardioversion for acute atrial fibrillationRandomized controlled trial · Moderate · ED acute AF population
ED rhythm-control strategy, procainamide, and electrical cardioversion in selected recent-onset AF.
- Citation
- Stiell IG, et al. Lancet. 2020;395:339–349.
- DOI / identifier
- 10.1016/S0140-6736(19)32994-0
12 EAST-AFNET 4: early rhythm-control therapy in atrial fibrillationRandomized controlled trial · High for enrolled early-AF population
Changes the longitudinal frame from symptom rescue alone to selected early rhythm control.
- Citation
- Kirchhof P, et al. N Engl J Med. 2020;383:1305–1316.
- DOI / identifier
- 10.1056/NEJMoa2019422
13 EHRA Practical Compendium of Antiarrhythmic DrugsExpert consensus · pharmacology compendium · Consensus plus drug-specific evidence
Owner-selected lead pharmacology source for ARR: drug mechanism, rate/state dependence, selection, PK/PD, interactions, safety, and monitoring; always paired with the correction record.
- Citation
- Merino JL, et al. Europace. 2025;27:euaf076; corrected March 2026.
- DOI / identifier
- 10.1093/europace/euaf076
- Correction / erratum
- March 17, 2026 correction DOI 10.1093/europace/euag041: mexiletine dosing/formulation row, amiodarone oral-maintenance footnote, and Table 17 lactation wording.
14 Correction to the EHRA Practical Compendium of Antiarrhythmic DrugsPost-publication correction · Definitive for the corrected article text
Mandatory dependency for any mexiletine dosing/formulation table, amiodarone oral-maintenance table, or Table 17 pregnancy/lactation interpretation derived from the 2025 compendium.
- Citation
- Europace. 2026;28:euag041. Published March 17, 2026.
- DOI / identifier
- 10.1093/europace/euag041
15 Ten key messages from the EHRA Practical Compendium of Antiarrhythmic DrugsExpert consensus · companion summary · Consensus summary; refer to full compendium for detail
Retrieval scaffold for the full compendium; never a substitute for corrected drug-specific detail.
- Citation
- European Heart Journal. 2026;47:ehaf805.
- DOI / identifier
- 10.1093/eurheartj/ehaf805
16 FDA approval of intranasal etripamil (Cardamyst) for adult PSVT self-treatmentRegulatory review + randomized trials · Approved indication; post-guideline
A living-evidence example: contemporary approved therapy that is not integrated into the older US/ESC SVT guidelines.
- Citation
- US Food and Drug Administration. Drug Trials Snapshot: Cardamyst. December 2025.
- DOI / identifier
- FDA approval record; RAPID trial DOI 10.1016/S0140-6736(23)00776-6
17 Effectiveness of the Valsalva manoeuvre for reversion of SVTSystematic review · Limited by heterogeneous, older studies
Evidence-synthesis layer used alongside, not as a substitute for, the later REVERT trial.
- Citation
- Smith GD, et al. Cochrane Database Syst Rev. 2015;CD009502.
- DOI / identifier
- 10.1002/14651858.CD009502.pub3
18 Wide QRS Complex TachycardiaTertiary clinical review · Orientation layer · verify management claims
Open-access scaffold for WCT definitions, mechanisms, differential diagnosis, and initial evaluation.
- Citation
- Obando MA, Marra EM. StatPearls [Internet]. Updated June 26, 2023.
- DOI / identifier
- Bookshelf ID NBK559054; PMID 32644480
19 Modified versus standard Valsalva for PSVT in an Indian emergency departmentRandomized controlled trial · new evidence · Low–moderate · small single-center trial
A current, imprecise replication signal used to teach confidence intervals, external context, and why one small trial does not erase REVERT.
- Citation
- Arora S, et al. Indian Heart J. 2026. Online ahead of print.
- DOI / identifier
- 10.1016/j.ihj.2026.02.004
Current arrhythmia work
ARR-01 stays active until you choose what follows.
Possible depth routes remain in the project map, but they are not a syllabus. The next build begins only when you name the gap—rhythm, drug, class, paper, or evidence question.
-
ARR-00
available
Baseline diagnostic assessment
Find the exact gaps in recognition, ECG logic, pharmacology, and bedside decisions.
-
ARR-01
active
Electrical foundations & rhythm classification
Conduction, action potentials, re-entry, automaticity, ECG intervals, and the pulse–stability–width–regularity framework.
-
→
unselected
Learner-selected next step
No automatic release follows ARR-01. Recommendations are offered only when requested.