Atrial Flutter, Emergency Medicine

Basics

Description

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 disease
- Infectious 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 abnormality
- More likely to recur and difficult to control

Essential Workup

EKG
Labs
CXR

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 cardioversion
- Start with 100 J

Initial Stabilization/Therapy

Oxygen, monitor, IV access
Immediate synchronized cardioversion if unstable
- Current 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 duration
  - Recommended even if negative transesophageal echo
  - Risk of thromboembolism ranges from 1.7-7%.
- 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)
Antiarrhythmic drugs:
- Adenosine:
  - Unlikely to break atrial flutter
  - May aid in the diagnosis of atrial flutter by unmasking the flutter waves
- Amiodarone:
  - Rate control in patients with pre-excited atrial arrhythmias (i.e., WPW)
  - Preferable antiarrhythmic agent for patients with severely impaired heart function
  - Major adverse effects are hypotension and bradycardia, slower infusions can prevent this.
- Calcium channel blockers:
  - Rate control
  - Verapamil has higher incidence of symptomatic hypotension than diltiazem.
  - Verapamil should only be used in narrow-complex arrhythmias
- β-blockers:
  - Rate control
  - Added benefit of cardioprotective effects for patients with ACS
- Magnesium sulfate:
  - Rate control
  - Low-level evidence
- Digoxin:
  - Rate control
  - 3rd-line drug
  - Has inotropic properties so may be useful in patients with ventricular dysfunction
  - Longer onset to therapeutic effect
- Procainamide:
  - Rhythm control
  - Drug of choice for patients with known pre-excitation syndromes (i.e., WPW) and preserved ventricular function
  - Caution if patient has QT prolongation
- Sotalol:
  - Rhythm control
  - Not a 1st-line drug
  - For use in WPW and preserved ventricular function if duration of arrhythmia is ≤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
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 flutter
- Amiodarone most effective
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

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 � 1. May give 12 mg IV q1-2min � 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 μg/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 μg 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 μg ORALLY twice daily; MAX. dose 500 μg 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 μg/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 controlled
- Underlying cause has been investigated and addressed
- Anticoagulation has been initiated
- Appropriate 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 �

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 control
- Prevention of systemic embolization
- Reversion to sinus rhythm
- Maintenance of sinus rhythm

Additional Reading

Clausen �H, Theophilos �T, Jackno �K, et al. Paediatric arrhythmias in the emergency department. Emerg Med J. 2012;29(9):732-737.
Fuster �V, Ryden �LE, Cannom �DS, 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 �G, Sanders �P, Kalman �JM. Catheter ablation of atrial arrhythmias: State of the art. Lancet. 2012;380(9852):1509-1519.
Scheuermeyer �FX, Grafstein �E, Heilbron �B, et al. Emergency department management and 1-year outcomes of patients with atrial flutter. Ann Emerg Med. 2011;57(6):564-571.
Stiell �IG, Macle �L; 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 �

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)

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