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Atrial Flutter, Emergency Medicine

Basics

Description

- CHADS2 score: Used for decision regarding anticoagulation - CHF history (1 point) - Hypertension history (1 point) - Age ≥75 (1 point) - DM history (1 point) - Stroke symptoms or TIA history (2 points): - Score 0: Aspirin is sufficient prophylaxis - Score 1: Oral anticoagulants preferred - Score 2 or more: Oral anticoagulants strongly recommended

- Patients at higher thromboembolism risk: - Valvular heart disease - Fluctuating a fib/flutter rhythms - Left ventricular (LV) dysfunction - Prior stroke or thromboembolism - Longer symptom duration (>48 hr)

- Ibutilide: - Rhythm control - For acute pharmacologic rhythm conversion in patients with preserved ventricular function (EF >30%) if duration of arrhythmia is ≤48 hr - Correct potassium and magnesium before use - Contraindicated if QTc >440 msec or in patients with severe structural heart disease - Efficacy rate of 38-76% - Mean time to conversion is 30 min. - Incidence of sustained polymorphic VT 1.2-1.7% - Observe for 4-6 hr after administration for QT prolongation or VT.

- Cardioversion: - 100-360 J - Sedation when possible - Safest and most effective means of restoring sinus rhythm

- Percutaneous catheter ablation: - Acute success rates exceed 95%. - 5-10% recurrence in 1-2 yr of follow-up - Low complication rate - Candidates include: - Recurrent episodes of drug-resistant atrial flutter - Patients who are drug intolerant - Patients who do not desire long-term drug therapy

- New-onset atrial flutter who meet these criteria: - Rate or rhythm has been controlled - Underlying cause has been investigated and addressed - Anticoagulation has been initiated - Appropriate follow-up is arranged

- Do not delay cardioversion in an unstable patient for IV placement. - Use β-blockers with caution in patients with pulmonary disease or CHF. - 4 major treatment issues: - Rate control - Prevention of systemic embolization - Reversion to sinus rhythm - Maintenance of sinus rhythm

  • Atrial dysrhythmia
  • 200,000 new cases each year
  • A macroreentrant circuit in the right atrium is thought to be the underlying mechanism.
  • Most sensitive rhythm to cardioversion
  • Seldom occurs in the absence of organic heart disease
  • Less common than supraventricular tachycardia (SVT) or atrial fibrillation
  • Typically paroxysmal, lasting seconds to hours
  • Occurs in ~25-35% of patients with atrial fibrillation
  • Untreated, may promote cardiomyopathy

Etiology

  • Alcoholism
  • Cardiomyopathies and myocarditis
  • CHF
  • Electrolyte abnormalities
  • Ischemic heart disease
  • Pulmonary embolus and other pulm diseases
  • Valvular heart diseases
  • Post op following cardiac surgery (often in 1st postoperative week)
  • Thyrotoxicosis
  • Occurs in children but is often asymptomatic
  • Associated mortality is highest in the neonatal period.
  • Associated with:Congenital heart diseaseInfectious etiologies, such as rheumatic fever or myocarditis
  • Be sure to consider potential toxic ingestions in pediatric patients with new AV block

Diagnosis

Signs and Symptoms

  • Palpitations
  • Syncope/presyncope
  • Chest pain
  • Fatigue
  • Dyspnea
  • Poor exercise capacity
  • Tachycardia-HR >150 bpm:
  • Hypotension
  • Heart failure
  • Infants do not tolerate atrial flutter well.
  • The aortic valve (AV) node is capable of very rapid conduction.
  • Extremely rapid ventricular rates can lead to shock or CHF.
  • Atrial flutter can occur in the fetus and young infants without associated cardiac defects:Often does not recur beyond neonatal period
  • Most older children have an underlying cardiac abnormalityMore likely to recur and difficult to control

Essential Workup

Diagnosis Tests & Interpretation

Lab

  • Electrolytes and mineral panel
  • Cardiac enzymes
  • Digoxin level
  • PT/PTT

Imaging

  • CXR:May identify cardiomyopathy or CHF
  • Echo:May identify regional wall motion abnormalities or valvular dysfunction

Differential Diagnosis

  • SVT
  • Sinus tachycardia
  • Atrial fibrillation
  • Multifocal atrial tachycardia
  • Ventricular tachycardia (VT)

Treatment

Pre-Hospital

  • Oxygen, monitor, IV access
  • Unstable patients should be cardioverted in the field:Immediate synchronized cardioversionStart with 100 J

Initial Stabilization/Therapy

  • Oxygen, monitor, IV access
  • Immediate synchronized cardioversion if unstableCurrent guidelines recommend starting at 150-200 J min to improve initial success and to limit cumulative energy doses.

Ed Treatment/Procedures

  • Rate control:Rate control should be instituted prior to giving an antidysrhythmic to avoid risk of a 1:1 AV conduction ratio and hemodynamic collapse.May be difficult to achieve
  • Anticoagulation:Same guidelines as for atrial fibrillation:INR 2-3 for 3 wk prior to cardioversion if >48 hr or unknown durationRecommended even if negative transesophageal echoRisk of thromboembolism ranges from 1.7-7%.CHADS2 score: Used for decision regarding anticoagulationCHF history (1 point)Hypertension history (1 point)Age ≥75 (1 point)DM history (1 point)Stroke symptoms or TIA history (2 points):Score 0: Aspirin is sufficient prophylaxisScore 1: Oral anticoagulants preferredScore 2 or more: Oral anticoagulants strongly recommendedPatients at higher thromboembolism risk:Valvular heart diseaseFluctuating a fib/flutter rhythmsLeft ventricular (LV) dysfunctionPrior stroke or thromboembolismLonger symptom duration (>48 hr)
  • Antiarrhythmic drugs:Adenosine:Unlikely to break atrial flutterMay aid in the diagnosis of atrial flutter by unmasking the flutter wavesAmiodarone:Rate control in patients with pre-excited atrial arrhythmias (i.e., WPW)Preferable antiarrhythmic agent for patients with severely impaired heart functionMajor adverse effects are hypotension and bradycardia, slower infusions can prevent this.Calcium channel blockers:Rate controlVerapamil has higher incidence of symptomatic hypotension than diltiazem.Verapamil should only be used in narrow-complex arrhythmiasβ-blockers:Rate controlAdded benefit of cardioprotective effects for patients with ACSMagnesium sulfate:Rate controlLow-level evidenceDigoxin:Rate control3rd-line drugHas inotropic properties so may be useful in patients with ventricular dysfunctionLonger onset to therapeutic effectProcainamide:Rhythm controlDrug of choice for patients with known pre-excitation syndromes (i.e., WPW) and preserved ventricular functionCaution if patient has QT prolongationSotalol:Rhythm controlNot a 1st-line drugFor use in WPW and preserved ventricular function if duration of arrhythmia is ≤48 hrIbutilide:Rhythm controlFor acute pharmacologic rhythm conversion in patients with preserved ventricular function (EF >30%) if duration of arrhythmia is ≤48 hrCorrect potassium and magnesium before useContraindicated if QTc >440 msec or in patients with severe structural heart diseaseEfficacy rate of 38-76%Mean time to conversion is 30 min.Incidence of sustained polymorphic VT 1.2-1.7%Observe for 4-6 hr after administration for QT prolongation or VT.
  • Cardioversion:100-360 JSedation when possibleSafest and most effective means of restoring sinus rhythm
  • Maintenance of sinus rhythm after cardioversion:High recurrence rate: ~50% at 1 yr; however, difficult to determine rate because data combines atrial fibrillation with atrial flutterAmiodarone most effective
  • Percutaneous catheter ablation:Acute success rates exceed 95%.5-10% recurrence in 1-2 yr of follow-upLow complication rateCandidates include:Recurrent episodes of drug-resistant atrial flutterPatients who are drug intolerantPatients who do not desire long-term drug therapy
  • Verapamil is not recommended in infants and young children as it is associated with a low cardiac output and serious cardiovascular compromise.
  • Digoxin is the 1st-line drug therapy for pediatric atrial flutter.
  • Consider cardioversion as 1st-line therapy in neonates.

Medication

  • Amiodarone: 150 mg IV over 10 min, then continuous infusion at 1 mg/min for 6 hr, then 0.5 mg/min infusion over 18 hr; supplemental 150 mg infusions can be dosed PRN to a max. daily dose of 2.2 g (peds: 5 mg/kg IV loading dose over 20-60 min, may repeat to max. of 15 mg/kg/d IV)
  • Adenosine: 6 mg IV пїЅ 1. May give 12 mg IV q1-2min пїЅ 2 if no conversion. Give all doses IV push
  • Atenolol: 5 mg IV over 5 min, may repeat in 10 min if tolerated, then 50 mg PO q12h
  • Digoxin: Loading dose 8-12 Ug/kg lean body weight, half of which is administered initially over 5 min, and remaining portion at 25% fractions at 4-8 hr intervals (peds: 8-12 Ојg/kg)
  • Diltiazem: 0.25 mg/kg IV over 2 min followed in 15 min by 0.35 mg/kg IV over 2 min, maintenance infusion of 10-15 mg/h titrated to heart rate
  • Dofetilide: CrCl >60 mL/min and QTc 440 msec or less) initial dose 500 Ојg ORALLY twice daily; determine QTc 2-3 h after 1st dose; if QTc increases by more than 15% OR is >500 msec (550 msec in patients with ventricular conduction abnormalities), reduce dose to 250 Ојg ORALLY twice daily; MAX. dose 500 Ојg ORALLY twice daily
  • Esmolol: 0.5 mg/kg over 1 min; maintenance infusion at 0.05 mg/kg/min; can repeat loading dose and increase in increments of 0.05 mg/kg/min q4min up to 0.3 mg/kg/min
  • Flecainide: A single dose of flecainide 300 mg (body weight 70 kg or greater), and flecainide 200 mg (body weight <70 kg) [3]; prior to antiarrhythmic initiation, a β-blocker or nondihydropyridine calcium channel antagonist should be administered to prevent rapid AV conduction if atrial flutter occurs
  • Ibutilide: 1 mg IV over 10 min for patients >60 kg; 0.01 mg/kg IV for patients <60 kg infused over 10 min; dose can be repeated once if normal sinus rhythm not restored within 10 min after infusion
  • Magnesium sulfate: 1-2 g diluted in D5W over 5-60 min; slower rate preferable if patient is stable.
  • Metoprolol: 5 mg IV push over 5 min at 5 min intervals to total of 15 mg, then 50 mg PO BID
  • Procainamide: 20 mg/min until arrhythmia suppressed, hypotension, QRS prolongation of 50%, or total of 17 mg/kg; may be given at rate up to 50 mg/min (peds: 15 mg/kg IV over 30 min, then 20-80 Ојg/kg/min continuous infusion)
  • Propranolol: 0.5-1 mg over 1 min, repeated after 2 min up to a total dose of 0.1 mg/kg (peds: 0.01-0.15 mg/kg/dose slow IV push over 5 min, max. 1 mg/dose)
  • Sotalol: 1-1.5 mg/kg over 5 min (US packaging recommends infusion over 5 h)
  • Verapamil: 2.5-5.0 mg IV bolus over 2 min; may repeat with 5-10 mg q15-30min to a max. of 20-30 mg.

Follow-Up

Disposition

Admission Criteria

  • New-onset atrial flutter requiring antidysrhythmics, rate control
  • Symptomatic (i.e., chest pain that warrants a rule out or cardioversion)
  • CHF

Discharge Criteria

  • New-onset atrial flutter who meet these criteria:Rate or rhythm has been controlledUnderlying cause has been investigated and addressedAnticoagulation has been initiatedAppropriate follow-up is arranged
  • Chronic atrial flutter with good rate control and appropriate anticoagulation

Followup Recommendations

Cardiologist: Radiofrequency ablation of atrial flutter emerging as treatment of choice for patients with symptomatic atrial flutter without identifiable reversible cause пїЅ

Pearls and Pitfalls

  • Be aware of WPW:Do not use adenosine, β-blockers, calcium channel blockers, and digoxin (Class III can be harmful).Can cause increased ventricular response, which can deteriorate to ventricular fibrillation
  • Do not delay cardioversion in an unstable patient for IV placement.
  • Use β-blockers with caution in patients with pulmonary disease or CHF.
  • 4 major treatment issues:Rate controlPrevention of systemic embolizationReversion to sinus rhythmMaintenance of sinus rhythm

Additional Reading

  • Clausen пїЅH, Theophilos пїЅT, Jackno пїЅK, et al. Paediatric arrhythmias in the emergency department. Emerg Med J. 2012;29(9):732-737.
  • Fuster пїЅV, Ryden пїЅLE, Cannom пїЅDS, et al. ACC/AHA/ESC 2006 Guidelines for the management of patients with atrial fibrillation. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines. J Am Coll Cardiol. 2006;48:e149.
  • Lee пїЅG, Sanders пїЅP, Kalman пїЅJM. Catheter ablation of atrial arrhythmias: State of the art. Lancet. 2012;380(9852):1509-1519.
  • Scheuermeyer пїЅFX, Grafstein пїЅE, Heilbron пїЅB, et al. Emergency department management and 1-year outcomes of patients with atrial flutter. Ann Emerg Med. 2011;57(6):564-571.
  • Stiell пїЅIG, Macle пїЅL; CCS Atrial Fibrillation Guidelines Committee. Canadian Cardiovascular Society atrial fibrillation guidelines 2010; management of recent-onset atrial fibrillation and flutter in the emergency department. Can J Cardiol. 2011;27(1):38-46.

Codes

ICD9

427.32 Atrial flutter пїЅ

ICD10

  • I48.3 Typical atrial flutter
  • I48.4 Atypical atrial flutter
  • I48.92 Unspecified atrial flutter

SNOMED

  • 5370000 Atrial flutter (disorder)
  • 427665004 paroxysmal atrial flutter (disorder)
  • 425615007 chronic atrial flutter (disorder)